New answers tagged solid-state-physics
1
vote
How to numerically compute the gap function $ |\Delta| $ as a function of energy from this self-consistent equation?
This is not a full answer. I am just trying to help a little. Your notation is very annoying to work with. The only appearance of $\Delta$ comes in the form of $|\Delta|^2$, so you actually lose ...
- 11.2k
0
votes
Doping with phosphorus
the extra electron in phosphorus finds itself a state in the conduction band while no hole is created thus increasing electron density while not changing hole density
Not true. Through the law of ...
- 1,686
1
vote
Doping with phosphorus
Regarding the extra proton in the phosphorus nucleus, you're correct that it does have an effect, but a small one. The additional positive charge of the proton slightly perturbs the potential energy ...
- 74
1
vote
Doping with phosphorus
The binding energy of the electron to the phosphorus is 44 meV. Phosphorus behaves like a scaled hydrogen atom with the complete set of excited states. At low temperatures the electron is bound but at ...
- 26.6k
1
vote
Form of wide-band limit for the broadening
Typically tunneling matrix elements are characterized not only by the index of state within the "interacting" region $\alpha$, but also the index of the lead from/to which the tunneling ...
- 65.1k
1
vote
How to perform Fourier transform of this Hamiltonian?
My understanding is that they try to rewrite the Hamiltonian as:
$$
H=\int \frac{d\Omega}{2\pi}\tilde{H}(\omega)e^{i\Omega t},
$$
where obviously
$$
\tilde{H}(\omega)=\int \frac{d\Omega}{2\pi}He^{-i\...
- 65.1k
0
votes
Cryostage solid state active insulation
The cooling power of Peltier effect stages drops to virtually nothing once you get to a 70K temperature difference between the hot and the cold sides of the device.
This means that a single-stage ...
- 155
1
vote
Why do not tiny cracks heal in metal via cold welding?
Indium repairs itself at room temperature but it is very soft with a melting temperature of 157C. The answer is therefore that at room temperature self diffusion in most metals is very much suppressed:...
- 26.6k
0
votes
Why do not tiny cracks heal in metal via cold welding?
It seems to me that the impurities that have coalesced at the triple points between the crystals forming the metal would be happy to migrate back along the crystal surfaces, preventing cold welding. ...
2
votes
A Particular Interaction Matrix in a Fully Connected Ising Model
When I first asked this question, I was honestly just hoping someone would swoop in with an example from condensed matter physics or statistical mechanics. Spoiler alert: nobody did. But the question ...
5
votes
DOS (density of states) in the vicinity of a band extremum point
It doesn't change, it's just that you're simplifying by approximating the density of states as parabolic near an extremum. Note that (in 1D for simplicity)
$$\int_{BZ} \delta\big(\epsilon- E(k)\big) \ ...
- 71.5k
0
votes
The origin of Joule heating from scattering
The following is a highly suggested viewpoint, but do check with an expert on the details.
The two statements are actually not in contradiction, despite being worded in such a way as to appear to be ...
- 11.2k
2
votes
Accepted
Understanding how band gaps come out of electron dispersion relations
You're right. The gray shading doesn't denote filled states, which are only located on the dispersion curves. In fact, each branch of the dispersion relation represents a single eigenstate of the ...
- 29.6k
2
votes
Physical reason for the diamagnetic behaviour of closed-shell atoms & the free electron gas
Let's work out the equations to see what we have. With the Hamiltonian of the system subjected to the field $\vec H$.
Diamagnetic Hamiltonian
$$
\mathcal H = \sum_k \frac{1}{2m} \left (\vec p_k^2 - \...
- 3,379
1
vote
Accepted
Two completely different-looking adiabatic connection formula in DFT
I have found the answer to my own question, so here is a brief summary. The equation
$$ E_{\lambda = 1} - E_{\lambda = 0} = \int^1_0 \mathrm{d}\lambda \left\langle \Psi_\lambda \middle| \hat{H} \...
- 926
1
vote
How do valence band electrons move within a semiconductor lattice?
Forget all the molecular bonding stuff and four electrons to an atom. The bonding is across the whole solid.
Electrons are in Bloch states in periodic solids; they are traveling plane waves.
The ...
- 459
1
vote
Why doesn't it require breaking a bond for a valence electron to fill a neighboring hole?
That professor is an electrical engineering professor and not a physics professor. He says the bond energy is 1.1 eV. That's the band gap in silicon. It is not a bond energy. Besides that, the idea of ...
- 459
0
votes
Understanding how band gaps come out of electron dispersion relations
You essentially have two questions: what's up with the grey-filled area, and how to get from the first dispersion relation to the others?
Regarding the different dispersion relations, at the moment, I ...
- 459
0
votes
Thermal expansion and stress analysis of rigidly joined rods
The relative thermal expansion (thermal strain) of each rod/plate individually is defined by the linear thermal expansion coefficient $ \Delta l / l_o = \alpha \Delta T$. Under thermal treatment, the ...
- 2,938
0
votes
Drift current and diffusion current in depletion region of diode at equilibrium
As the question itself explains: the net current is zero in equilibrium (when $V_A=0$), and not zero out of equilirbium (when $V_A\neq 0$.) This is reflected in the current-voltage characteristic, ...
- 65.1k
Top 50 recent answers are included