The main obstacles in realizing diluted magnetic oxide (DMO) in spintronics are the unknown elect... more The main obstacles in realizing diluted magnetic oxide (DMO) in spintronics are the unknown electronic structures associated with its high TC ferromagnetism and spin polarized current and how to manipulate desired electronic structures by fabrication techniques. We demonstrate that fine-tuned electronic structures and band structures can be modified to initiate DMO properties. Interestingly, in the semiconducting state, the doped Co ions and oxygen vacancies contribute non-negligible magnetic moments; and the magnetic coupling between these moments is mediated by the localized carriers via highly spin polarized hopping transport. These results unravel the myth of the origin of spintronic characteristics with desirable electronic states; thereby reopening the door for future applications.
Abstract We proposed a theoretical model to simulate the ferromagnetism in n-type ZnO. The model ... more Abstract We proposed a theoretical model to simulate the ferromagnetism in n-type ZnO. The model suggests that ferromagnetism arises from the spin split of the electrons in the dopant-induced impurity states by Coulomb excitation. The ferromagnetism is closely dependent on the carrier density and the energy of the dopant-impurity states relative to the conduction band edge. The theory simulates the temperature-dependent magnetization increasing with the temperature and is consistent with the experimental results. The theoretical results imply that the origin of ferromagnetism includes coexisting bound magnetic polaron and carrier medium mechanisms.
This work demonstrated the enhanced photodegradation (PD) resulting from Co-rich doping of ZnO na... more This work demonstrated the enhanced photodegradation (PD) resulting from Co-rich doping of ZnO nanowire (NW) surfaces (Co2+/ZnO NWs) prepared by combining Co sputtering on ZnO NWs and immersion in deionized water to exploit the hydrophilic-hydrophobic transitions on the ZnO surfaces resulting from Co atom diffusion. Because of the controllable spin-dependent density of states (DOS) induced by Co2+, the PD of methylene blue dye can be enhanced by approximately 90% (when compared with bare ZnO NWs) by using a conventional permanent magnet with a relatively low magnetic field strength of approximately 0.15 T. The reliability of spin polarization-modulation attained through surface doping, based on the magnetic response observed from X-ray absorption measurements and magnetic circular dichroism, provides an opportunity to create highly efficient catalysts by engineering surfaces and tailoring their spin-dependent DOS.
In this work, electrical manipulation of the magneto-optical properties of a cobalt (Co)/carbon (... more In this work, electrical manipulation of the magneto-optical properties of a cobalt (Co)/carbon (C) heterostructure is demonstrated via reversible voltage (V)-dependent magnetic circular dichroism (MCD) measurements to provide information on its spin-polarized density of states. Complex impedance spectroscopy revealed the occurrence of capacitance effects between Co and C. Suppression of the radial distribution functions of the X-ray absorption spectra and changes in the Raman spectra reveal that charge injection under an applied V results in increased interstitial charge densities. Angle-dependent changes in MCD under an applied V reveal that variations in C-Co hybridization due to charge accumulation are responsible for the observed phenomena.
For the symmetric periodic Anderson model at half-filling, we emplloy the multiple-slave-boson te... more For the symmetric periodic Anderson model at half-filling, we emplloy the multiple-slave-boson technique, suitable for finite local Coulomb repulsion, at the mean-field level and build in the antiferromagnetism by dividing the lattice into two sublattices. For the one-dimensional case, antiferromagnetism appears for large U. In infinite dimension~, the Vdependence of the N6el temperature is tongue-like, and antiferromagnetism is stable only when Vis below a critical value.
As gold-nanoparticles–embedded in amorphous carbon films the sp 3 carbon orbits near the interfac... more As gold-nanoparticles–embedded in amorphous carbon films the sp 3 carbon orbits near the interface will be partially transferred to sp 2. The Raman spectrum measurements as well as the molecular-dynamics simulations used the second reactive empirical bond order (REBO) potential simulating the interatomic force between carbon atoms both confirm the orbital transformations. The amorphous carbon films are initially inert to gases, while the films embedded with gold nanoparticles exhibit the increase of resistance in ammonia atmosphere. Namely, gold-nanoparticles–embedded amorphous carbon films become the candidate for ammonia gas sensor materials.
We show that a special kind of slave-boson mean-field approximation, which allows for the symmetr... more We show that a special kind of slave-boson mean-field approximation, which allows for the symmetry-broken states appropriate for a bipartite lattice, can give essentially the same results as those by the variational-wave-function approach proposed by Gulacsi, Strack, and Vollhardt [Phys. Rev. B 47, 8594 (1993)]. The advantages of our approach are briefly discussed
The simulated annealing basin-hopping (SABH) method incorporating the penalty function was used t... more The simulated annealing basin-hopping (SABH) method incorporating the penalty function was used to predict the lowest-energy structures for SiO 2 nanowires of different sizes. The eight lowest-energy structures for different nanowire sizes were predicted, including two-, three-, four-, and five-membered structures (2MR, 2MR-2O, 3MR-3O, 4MR-4O, and 5MR-5O), 4MR-3facet, 4MR-4facet, and 4MR-5facet (4MR-3f, 4MR-4f, and 4MR-5f). A previous experimental study (Liu et al. ACS Nano 2009, 3 (5), 1160−1166) successfully synthesized silica nanotubes in a confined CNT cylindrical space and found various structures along a range of CNT diameters from 1.2 to 1.4 nm. At diameters larger than 1.7 nm, a disordered structure formed, different from the double-ladder SiO 2 structures. This simulation's predicted structures are in good agreement with this experimental result for 4MR and 5MR structures. In addition, this work predicted 4MR-3f, 4MR-4f, and 4MR-5f structures, which were not found in previous experimental work. Finally, we further investigate the structural and electronic properties of these ultrathin silica nanowires by density functional theory (DFT) calculation.
This study uses molecular dynamics simulations to investigate the crystalline process of Co-Cu na... more This study uses molecular dynamics simulations to investigate the crystalline process of Co-Cu nanoparticles of high and low Co concentrations (5 and 25%) during the annealing process. The modified many-body tight-binding potential involving magnetic contribution is adopted to accurately model the Cu-Cu, Co-Co, and Co-Cu pair interactions. The Co-Co bond length increases, while the Co-Cu bond length decreases as the temperature gradually drops from 2000 K to the upper melting point. During that process, the Cu-Cu bond length remains constant and the value of the first peak of the radial distribution function (RDF) increases, which indicates that Cu atoms increase their short-range order by mutual rearrangement. At temperatures lower than the upper melting point, the bond length of each pair decreases while the value of the first peak increases as the temperature is continuously reduced. Because the kinetic energy of an individual atom is not enough for rearrangement, the variations of bond length and the first RDF peak can be attributed to the shrinking effect.
We propose a hybridization model to simulate a molecular wire coupling with the environmental mol... more We propose a hybridization model to simulate a molecular wire coupling with the environmental molecules. Results reveal that the conduction transition from conducting to semiconducting depends on the coupling strength. In our simulations, the non-equilibrium Green's function method is employed to calculate the current-voltage relationship for the molecular wire through metallic contacts. Our calculations show that the band gap can be manipulated from the outside molecules coupling. Temperature dependence of the conductivity is represented in our results with strong dependence in high temperature range, which is qualitatively comparable with the experimental results of DNA. In our results, with small coupling, the current is enhanced by the exchange. On the contrary, too large a coupling results in localization of the transport carriers, leading to a semiconducting like property. We try to associate this study with the conducting property of DNA, which can be manipulated by environmental modulation.
We studied the diluted magnetic semiconductor by the self-consistent Green's function approach, w... more We studied the diluted magnetic semiconductor by the self-consistent Green's function approach, which treats the spin-wave kinematics appropriately at finite temperatures. Our approach leads to a simple formula for the critical temperature in a wide range of parameter space. In addition, the magnetization curve versus temperature in some regimes is concave, which is dramatically different from the usual convex shape. Finally, we discuss the possibility of generalizing the current theory to include the realistic band structure, electronic correlations and disorders in a systematic way.
We study the electronic transport in a molecular junction, in which each unit is coupled to a loc... more We study the electronic transport in a molecular junction, in which each unit is coupled to a local phonon bath, using the non-equilibrium Green's function method. We observe the conductance oscillates with the molecular chain length and the oscillation period in odd-numbered chains depends strongly on the applied bias. This oscillatory behavior is smeared out at the bias voltage near the phonon energy. For the phonon-free case, we find a crossover from tunneling to thermally activated transport as the length of the molecule increases. In the presence of electron-phonon interaction, the transport is thermally driven and a crossover from the thermally suppressed to assisted conduction is observed.
Zinc oxide (ZnO) that contains non-magnetic ionic dopants, such as nitrogen (N)-doped zinc oxide ... more Zinc oxide (ZnO) that contains non-magnetic ionic dopants, such as nitrogen (N)-doped zinc oxide (ZnO:N), has been observed to exhibit ferromagnetism. Ferromagnetism is proposed to arise from the Coulomb excitation in the localized states that is induced by the oxygen vacancy, V O. A model based on the Coulomb excitation that is associated with the electron–phonon interaction theoretically explains the ferromagnetic mechanism of ZnO:N. This study reveals that the ferromagnetism will be induced by either deep localized states with a small V O concentration or shallow localized states with a high V O concentration. Additionally, electron–phonon coupling either suppresses the ferromagnetism that is induced by the deep donor states of V O or enhances the ferromagnetism that is induced by the shallow donor states of V O.
The softening effects of ferromagnetic magnon on some ferromagnetic semiconductors and colossal m... more The softening effects of ferromagnetic magnon on some ferromagnetic semiconductors and colossal magnetoresistance manganites have attracted much attention. Such effect can be calculated from the single-orbital ferromagnetic Kondo lattice model in proper conducting carrier numbers utilizing the equation of motion method with one magnon excitation and random phase approximations. However, if we take into account the Coulomb repulsion and use the Gutzwiller projection method to transfer this repulsion force to conducting bandwidth modulation, the softening effects disappear. This paper describes qualitively the effect of softening on properties of different colossal manganites.
Molecular dynamics simulations and quantum transport theory are employed to study the temperature... more Molecular dynamics simulations and quantum transport theory are employed to study the temperature-dependent electrical properties of individual (12,0) zigzag and (5,5) armchair carbon nanotubes deposited on silicon substrates. The results demonstrate that the magnitude of the leakage current depends on the length of the nanotube. Furthermore, the leakage current is generated periodically along the length of the nanotube. Finally, the results indicate that given an appropriate value of the applied bias voltage, the induced current varies linearly with the temperature over specific temperature ranges. As a result, the temperature can be inversely derived from the measured current signal. Overall, the results show that the (12,0) zigzag and (5,5) armchair carbon nanotubes are suitable for temperature sensing applications over temperature ranges of 200-420 K and 300-440 K, respectively.
Nitrogen embedded ZnO : N films prepared by pulsed laser deposition exhibit significant ferromagn... more Nitrogen embedded ZnO : N films prepared by pulsed laser deposition exhibit significant ferromagnetism. The presence of nitrogen ions contained in ZnO is confirmed by the secondary ion microscopic spectrum and by Raman experiments, and the embedded nitrogen ions can be regarded as defects. According to the experimental results, a mechanism is proposed based on one of the electrons in the completely filled d-orbits of Zn that compensates the dangling bonds of nitrogen ions and leads to a net spin of one-half in the Zn orbits. These one-half spins strongly correlate with localized electrons that are captured by defects to form ferromagnetism. Eventually, the magnetism of nitrogen embedded ZnO : N films could be described by a bound magnetic polaron model.
Amorphous aluminium-doped zinc oxide (AZO) thin films are grown by standard RF sputtering at low ... more Amorphous aluminium-doped zinc oxide (AZO) thin films are grown by standard RF sputtering at low temperatures on glass substrates. Due to poor thermal conductivity and thermal energy generated by the sputter gun, controlling the substrate surface temperature is the key to controlling the growth of amorphous and nanocrystalline films. The ratio of grains and amorphous part of the films can be controlled by selective growth conditions. During a transmission electron microscope (TEM) inspection process, the amorphous films react immediately and strongly with an electron beam and transform to a mixture of amorphous and nanocrystalline phases. The films having a mixture of amorphous and nanocrystalline phases, either as-grown or after transformation by irradiation of the electron beam, are stable in the TEM inspection, indicating that the low interface energy stabilizes the mixture phase. The optical band gap increases with the content of amorphous phase and is 4.3 eV for pure amorphous AZO films.
ABSTRACT This study employs the self-consistent Green's function method to study the magn... more ABSTRACT This study employs the self-consistent Green's function method to study the magnetic properties of diluted CoxCu1-x alloys from a consideration of their spin dynamics characteristics. The numerical results show that in dilute cobalt concentrations (i.e. x⩽0.4), the critical temperatures vary linearly with x for different itinerant carrier concentration conditions. Interestingly, the carrier concentration does not affect the degree of dependency of the temperature on the cobalt concentration when the carrier concentration is less than the atomic number concentration of the alloy.
The main obstacles in realizing diluted magnetic oxide (DMO) in spintronics are the unknown elect... more The main obstacles in realizing diluted magnetic oxide (DMO) in spintronics are the unknown electronic structures associated with its high TC ferromagnetism and spin polarized current and how to manipulate desired electronic structures by fabrication techniques. We demonstrate that fine-tuned electronic structures and band structures can be modified to initiate DMO properties. Interestingly, in the semiconducting state, the doped Co ions and oxygen vacancies contribute non-negligible magnetic moments; and the magnetic coupling between these moments is mediated by the localized carriers via highly spin polarized hopping transport. These results unravel the myth of the origin of spintronic characteristics with desirable electronic states; thereby reopening the door for future applications.
Abstract We proposed a theoretical model to simulate the ferromagnetism in n-type ZnO. The model ... more Abstract We proposed a theoretical model to simulate the ferromagnetism in n-type ZnO. The model suggests that ferromagnetism arises from the spin split of the electrons in the dopant-induced impurity states by Coulomb excitation. The ferromagnetism is closely dependent on the carrier density and the energy of the dopant-impurity states relative to the conduction band edge. The theory simulates the temperature-dependent magnetization increasing with the temperature and is consistent with the experimental results. The theoretical results imply that the origin of ferromagnetism includes coexisting bound magnetic polaron and carrier medium mechanisms.
This work demonstrated the enhanced photodegradation (PD) resulting from Co-rich doping of ZnO na... more This work demonstrated the enhanced photodegradation (PD) resulting from Co-rich doping of ZnO nanowire (NW) surfaces (Co2+/ZnO NWs) prepared by combining Co sputtering on ZnO NWs and immersion in deionized water to exploit the hydrophilic-hydrophobic transitions on the ZnO surfaces resulting from Co atom diffusion. Because of the controllable spin-dependent density of states (DOS) induced by Co2+, the PD of methylene blue dye can be enhanced by approximately 90% (when compared with bare ZnO NWs) by using a conventional permanent magnet with a relatively low magnetic field strength of approximately 0.15 T. The reliability of spin polarization-modulation attained through surface doping, based on the magnetic response observed from X-ray absorption measurements and magnetic circular dichroism, provides an opportunity to create highly efficient catalysts by engineering surfaces and tailoring their spin-dependent DOS.
In this work, electrical manipulation of the magneto-optical properties of a cobalt (Co)/carbon (... more In this work, electrical manipulation of the magneto-optical properties of a cobalt (Co)/carbon (C) heterostructure is demonstrated via reversible voltage (V)-dependent magnetic circular dichroism (MCD) measurements to provide information on its spin-polarized density of states. Complex impedance spectroscopy revealed the occurrence of capacitance effects between Co and C. Suppression of the radial distribution functions of the X-ray absorption spectra and changes in the Raman spectra reveal that charge injection under an applied V results in increased interstitial charge densities. Angle-dependent changes in MCD under an applied V reveal that variations in C-Co hybridization due to charge accumulation are responsible for the observed phenomena.
For the symmetric periodic Anderson model at half-filling, we emplloy the multiple-slave-boson te... more For the symmetric periodic Anderson model at half-filling, we emplloy the multiple-slave-boson technique, suitable for finite local Coulomb repulsion, at the mean-field level and build in the antiferromagnetism by dividing the lattice into two sublattices. For the one-dimensional case, antiferromagnetism appears for large U. In infinite dimension~, the Vdependence of the N6el temperature is tongue-like, and antiferromagnetism is stable only when Vis below a critical value.
As gold-nanoparticles–embedded in amorphous carbon films the sp 3 carbon orbits near the interfac... more As gold-nanoparticles–embedded in amorphous carbon films the sp 3 carbon orbits near the interface will be partially transferred to sp 2. The Raman spectrum measurements as well as the molecular-dynamics simulations used the second reactive empirical bond order (REBO) potential simulating the interatomic force between carbon atoms both confirm the orbital transformations. The amorphous carbon films are initially inert to gases, while the films embedded with gold nanoparticles exhibit the increase of resistance in ammonia atmosphere. Namely, gold-nanoparticles–embedded amorphous carbon films become the candidate for ammonia gas sensor materials.
We show that a special kind of slave-boson mean-field approximation, which allows for the symmetr... more We show that a special kind of slave-boson mean-field approximation, which allows for the symmetry-broken states appropriate for a bipartite lattice, can give essentially the same results as those by the variational-wave-function approach proposed by Gulacsi, Strack, and Vollhardt [Phys. Rev. B 47, 8594 (1993)]. The advantages of our approach are briefly discussed
The simulated annealing basin-hopping (SABH) method incorporating the penalty function was used t... more The simulated annealing basin-hopping (SABH) method incorporating the penalty function was used to predict the lowest-energy structures for SiO 2 nanowires of different sizes. The eight lowest-energy structures for different nanowire sizes were predicted, including two-, three-, four-, and five-membered structures (2MR, 2MR-2O, 3MR-3O, 4MR-4O, and 5MR-5O), 4MR-3facet, 4MR-4facet, and 4MR-5facet (4MR-3f, 4MR-4f, and 4MR-5f). A previous experimental study (Liu et al. ACS Nano 2009, 3 (5), 1160−1166) successfully synthesized silica nanotubes in a confined CNT cylindrical space and found various structures along a range of CNT diameters from 1.2 to 1.4 nm. At diameters larger than 1.7 nm, a disordered structure formed, different from the double-ladder SiO 2 structures. This simulation's predicted structures are in good agreement with this experimental result for 4MR and 5MR structures. In addition, this work predicted 4MR-3f, 4MR-4f, and 4MR-5f structures, which were not found in previous experimental work. Finally, we further investigate the structural and electronic properties of these ultrathin silica nanowires by density functional theory (DFT) calculation.
This study uses molecular dynamics simulations to investigate the crystalline process of Co-Cu na... more This study uses molecular dynamics simulations to investigate the crystalline process of Co-Cu nanoparticles of high and low Co concentrations (5 and 25%) during the annealing process. The modified many-body tight-binding potential involving magnetic contribution is adopted to accurately model the Cu-Cu, Co-Co, and Co-Cu pair interactions. The Co-Co bond length increases, while the Co-Cu bond length decreases as the temperature gradually drops from 2000 K to the upper melting point. During that process, the Cu-Cu bond length remains constant and the value of the first peak of the radial distribution function (RDF) increases, which indicates that Cu atoms increase their short-range order by mutual rearrangement. At temperatures lower than the upper melting point, the bond length of each pair decreases while the value of the first peak increases as the temperature is continuously reduced. Because the kinetic energy of an individual atom is not enough for rearrangement, the variations of bond length and the first RDF peak can be attributed to the shrinking effect.
We propose a hybridization model to simulate a molecular wire coupling with the environmental mol... more We propose a hybridization model to simulate a molecular wire coupling with the environmental molecules. Results reveal that the conduction transition from conducting to semiconducting depends on the coupling strength. In our simulations, the non-equilibrium Green's function method is employed to calculate the current-voltage relationship for the molecular wire through metallic contacts. Our calculations show that the band gap can be manipulated from the outside molecules coupling. Temperature dependence of the conductivity is represented in our results with strong dependence in high temperature range, which is qualitatively comparable with the experimental results of DNA. In our results, with small coupling, the current is enhanced by the exchange. On the contrary, too large a coupling results in localization of the transport carriers, leading to a semiconducting like property. We try to associate this study with the conducting property of DNA, which can be manipulated by environmental modulation.
We studied the diluted magnetic semiconductor by the self-consistent Green's function approach, w... more We studied the diluted magnetic semiconductor by the self-consistent Green's function approach, which treats the spin-wave kinematics appropriately at finite temperatures. Our approach leads to a simple formula for the critical temperature in a wide range of parameter space. In addition, the magnetization curve versus temperature in some regimes is concave, which is dramatically different from the usual convex shape. Finally, we discuss the possibility of generalizing the current theory to include the realistic band structure, electronic correlations and disorders in a systematic way.
We study the electronic transport in a molecular junction, in which each unit is coupled to a loc... more We study the electronic transport in a molecular junction, in which each unit is coupled to a local phonon bath, using the non-equilibrium Green's function method. We observe the conductance oscillates with the molecular chain length and the oscillation period in odd-numbered chains depends strongly on the applied bias. This oscillatory behavior is smeared out at the bias voltage near the phonon energy. For the phonon-free case, we find a crossover from tunneling to thermally activated transport as the length of the molecule increases. In the presence of electron-phonon interaction, the transport is thermally driven and a crossover from the thermally suppressed to assisted conduction is observed.
Zinc oxide (ZnO) that contains non-magnetic ionic dopants, such as nitrogen (N)-doped zinc oxide ... more Zinc oxide (ZnO) that contains non-magnetic ionic dopants, such as nitrogen (N)-doped zinc oxide (ZnO:N), has been observed to exhibit ferromagnetism. Ferromagnetism is proposed to arise from the Coulomb excitation in the localized states that is induced by the oxygen vacancy, V O. A model based on the Coulomb excitation that is associated with the electron–phonon interaction theoretically explains the ferromagnetic mechanism of ZnO:N. This study reveals that the ferromagnetism will be induced by either deep localized states with a small V O concentration or shallow localized states with a high V O concentration. Additionally, electron–phonon coupling either suppresses the ferromagnetism that is induced by the deep donor states of V O or enhances the ferromagnetism that is induced by the shallow donor states of V O.
The softening effects of ferromagnetic magnon on some ferromagnetic semiconductors and colossal m... more The softening effects of ferromagnetic magnon on some ferromagnetic semiconductors and colossal magnetoresistance manganites have attracted much attention. Such effect can be calculated from the single-orbital ferromagnetic Kondo lattice model in proper conducting carrier numbers utilizing the equation of motion method with one magnon excitation and random phase approximations. However, if we take into account the Coulomb repulsion and use the Gutzwiller projection method to transfer this repulsion force to conducting bandwidth modulation, the softening effects disappear. This paper describes qualitively the effect of softening on properties of different colossal manganites.
Molecular dynamics simulations and quantum transport theory are employed to study the temperature... more Molecular dynamics simulations and quantum transport theory are employed to study the temperature-dependent electrical properties of individual (12,0) zigzag and (5,5) armchair carbon nanotubes deposited on silicon substrates. The results demonstrate that the magnitude of the leakage current depends on the length of the nanotube. Furthermore, the leakage current is generated periodically along the length of the nanotube. Finally, the results indicate that given an appropriate value of the applied bias voltage, the induced current varies linearly with the temperature over specific temperature ranges. As a result, the temperature can be inversely derived from the measured current signal. Overall, the results show that the (12,0) zigzag and (5,5) armchair carbon nanotubes are suitable for temperature sensing applications over temperature ranges of 200-420 K and 300-440 K, respectively.
Nitrogen embedded ZnO : N films prepared by pulsed laser deposition exhibit significant ferromagn... more Nitrogen embedded ZnO : N films prepared by pulsed laser deposition exhibit significant ferromagnetism. The presence of nitrogen ions contained in ZnO is confirmed by the secondary ion microscopic spectrum and by Raman experiments, and the embedded nitrogen ions can be regarded as defects. According to the experimental results, a mechanism is proposed based on one of the electrons in the completely filled d-orbits of Zn that compensates the dangling bonds of nitrogen ions and leads to a net spin of one-half in the Zn orbits. These one-half spins strongly correlate with localized electrons that are captured by defects to form ferromagnetism. Eventually, the magnetism of nitrogen embedded ZnO : N films could be described by a bound magnetic polaron model.
Amorphous aluminium-doped zinc oxide (AZO) thin films are grown by standard RF sputtering at low ... more Amorphous aluminium-doped zinc oxide (AZO) thin films are grown by standard RF sputtering at low temperatures on glass substrates. Due to poor thermal conductivity and thermal energy generated by the sputter gun, controlling the substrate surface temperature is the key to controlling the growth of amorphous and nanocrystalline films. The ratio of grains and amorphous part of the films can be controlled by selective growth conditions. During a transmission electron microscope (TEM) inspection process, the amorphous films react immediately and strongly with an electron beam and transform to a mixture of amorphous and nanocrystalline phases. The films having a mixture of amorphous and nanocrystalline phases, either as-grown or after transformation by irradiation of the electron beam, are stable in the TEM inspection, indicating that the low interface energy stabilizes the mixture phase. The optical band gap increases with the content of amorphous phase and is 4.3 eV for pure amorphous AZO films.
ABSTRACT This study employs the self-consistent Green's function method to study the magn... more ABSTRACT This study employs the self-consistent Green's function method to study the magnetic properties of diluted CoxCu1-x alloys from a consideration of their spin dynamics characteristics. The numerical results show that in dilute cobalt concentrations (i.e. x⩽0.4), the critical temperatures vary linearly with x for different itinerant carrier concentration conditions. Interestingly, the carrier concentration does not affect the degree of dependency of the temperature on the cobalt concentration when the carrier concentration is less than the atomic number concentration of the alloy.
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Papers by Shih-Jye Sun