Ilaria Maccari

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David Seamon

Kansas State University

Francisco J. [Paco] Bethencourt Llobet

Universidad Complutense de Madrid

Stephanie Seul

University of Bremen

Sean Nye

University of Southern California

Alejandro L. Madrid

Harvard University

Marek Titien Olszewski (Marek Tycjan Olszewski)

University of Warsaw

Antonio Salvatore Romano

Pontificia Facoltà Teologica dell'Italia Meridionale

Agostino Paravicini Bagliani

University of Lausanne

Jakob Tanner

University of Zurich, Switzerland

Maria Pia Donato

Centre National de la Recherche Scientifique / French National Centre for Scientific Research

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Papers by Ilaria Maccari

Phenomenological XXZ model for the competition between superconductivity and charge order in cuprates

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Sharpness of the Berezinskii-Kosterlitz-Thouless Transition in Disordered NbN Films

Physical Review Letters

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A numerical study of planar arrays of correlated spin islands

European Physical Journal B, May 1, 2016

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Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene

Physical review, Feb 7, 2023

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Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component London models

Physical review, Jun 24, 2022

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Disordered XY model: Effective medium theory and beyond

Physical review, Mar 11, 2019

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Broadening of the Berezinskii-Kosterlitz-Thouless transition by correlated disorder

Physical review, Aug 28, 2017

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Superfluid Properties of Superconductors with Disorder at the Nanoscale: A Random Impedance Model

Condensed matter, May 14, 2020

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Superfluid response of two-dimensional filamentary superconductors

arXiv (Cornell University), Apr 14, 2023

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Vortex supersolid in the XY model with tunable vortex fugacity

arXiv (Cornell University), Feb 27, 2023

Transport signatures of fragile glass dynamics in the melting of the two-dimensional vortex lattice

Physical Review B

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Calorimetric evidence for two phase transitions in Ba1-xKxFe2As2 with fermion pairing and quadrupling states

Materials that break multiple symmetries allow, under certain conditions, the formation of four-f... more Materials that break multiple symmetries allow, under certain conditions, the formation of four-fermion condensates above the superconducting critical temperature (Tc). Such states can be stabilized by phase fluctuations. Recently a fermionic quadrupling condensate that breaks the Z2 time-reversal symmetry was reported in Ba1-xKxFe2As2 [V. Grinenko et al., Nat. Phys. 17, 1254 (2021)]. However, the related anomaly was not resolved in the specific heat measurements. Resolving two anomalies at Tc and the Z2 transition temperature (TcZ2 > Tc) is key evidence for the existence of two distinct electronic phases. In a broader context, the lack of an additional anomaly in the specific heat at TcZ2 is a common unsolved problem for most superconductors with broken time-reversal symmetry, even in the conventional case where TcZ2 < Tc. Here, we report on detecting two anomalies in the specific heat of Ba1-xKxFe2As2 at zero magnetic field. The anomaly at the higher temperature is accompani...

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Possible time-reversal-symmetry-breaking fermionic quadrupling condensate in twisted bilayer graphene

arXiv (Cornell University), Jun 6, 2022

$Research paper thumbnail of Calorimetric evidence for two phase transitions in Ba$_{\rm 1-x}$K$_{\rm x}$Fe$_{2}$As$_{2}$ with fermion pairing and quadrupling states$

Calorimetric evidence for two phase transitions in Ba$_{\rm 1-x}$K$_{\rm x}$Fe$_{2}$As$_{2}$ with fermion pairing and quadrupling states

arXiv (Cornell University), Dec 27, 2022

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Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene

Physical Review B

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Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component London models

Physical Review B

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Interplay of spin waves and vortices in the 2D XY model at small vortex-core energy

The Berezinskii-Kosterlitz-Thouless (BKT) mechanism describes universal vortex unbinding in many ... more The Berezinskii-Kosterlitz-Thouless (BKT) mechanism describes universal vortex unbinding in many two-dimensional systems, including the paradigmatic XY model. However, most of these systems present a complex interplay between excitations at different length scales that complicates theoretical calculations of nonuniversal thermodynamic quantities. These difficulties may be overcome by suitably modifying the initial conditions of the BKT flow equations to account for noncritical fluctuations at small length scales. In this work, we perform a systematic study of the validity and limits of this two-step approach by constructing optimised initial conditions for the BKT flow. We find that the two-step approach can accurately reproduce the results of Monte-Carlo simulations of the traditional XY model. In order to systematically study the interplay between vortices and spin-wave excitations, we introduce a modified XY model with increased vortex fugacity. We present large-scale Monte-Carlo...

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Finite-Frequency Dissipation in Two-Dimensional Superconductors with Disorder at the Nanoscale

Nanomaterials, 2021

Two-dimensional superconductors with disorder at the nanoscale can host a variety of intriguing p... more Two-dimensional superconductors with disorder at the nanoscale can host a variety of intriguing phenomena. The superconducting transition is marked by a broad percolative transition with a long tail of the resistivity as function of the temperature. The fragile filamentary superconducting clusters, forming at low temperature, can be strengthened further by proximity effect with the surrounding metallic background, leading to an enhancement of the superfluid stiffness well below the percolative transition. Finite-frequency dissipation effects, e.g., related to the appearance of thermally excited vortices, can also significantly contribute to the resulting physics. Here, we propose a random impedance model to investigate the role of dissipation effects in the formation and strengthening of fragile superconducting clusters, discussing the solution within the effective medium theory.

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Bosonic Z2 metal: Spontaneous breaking of time-reversal symmetry due to Cooper pairing in the resistive state of Ba1−xKxFe2As2

Bosonic Z2 metal: Spontaneous breaking of time-reversal symmetry due to Cooper pairing in the res... more

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Uniformly Frustrated XY Model: Strengthening of the Vortex Lattice by Intrinsic Disorder

Condensed Matter, 2021

In superconducting films, the role of intrinsic disorder is typically to compete with superconduc... more In superconducting films, the role of intrinsic disorder is typically to compete with superconductivity by fragmenting the global phase coherence and lowering the superfluid density. Nonetheless, when a transverse magnetic field is applied to the system and an Abrikosov vortex lattice form, the presence of disorder can actually strengthen the superconducting state against thermal fluctuations. By means of Monte Carlo simulations on the uniformly frustrated XY model in two dimensions, we show that while for weak pinning the superconducting critical temperature Tc increases with the applied field H, for strong enough pinning, the experimental decreasing dependence between Tc and H is recovered with a resulting more robust vortex lattice.

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Phenomenological XXZ model for the competition between superconductivity and charge order in cuprates

Download

Sharpness of the Berezinskii-Kosterlitz-Thouless Transition in Disordered NbN Films

Physical Review Letters

Download

A numerical study of planar arrays of correlated spin islands

European Physical Journal B, May 1, 2016

Download

Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene

Physical review, Feb 7, 2023

Download

Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component London models

Physical review, Jun 24, 2022

Download

Disordered XY model: Effective medium theory and beyond

Physical review, Mar 11, 2019

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Broadening of the Berezinskii-Kosterlitz-Thouless transition by correlated disorder

Physical review, Aug 28, 2017

Download

Superfluid Properties of Superconductors with Disorder at the Nanoscale: A Random Impedance Model

Condensed matter, May 14, 2020

Download

Superfluid response of two-dimensional filamentary superconductors

arXiv (Cornell University), Apr 14, 2023

Download

Vortex supersolid in the XY model with tunable vortex fugacity

arXiv (Cornell University), Feb 27, 2023

Transport signatures of fragile glass dynamics in the melting of the two-dimensional vortex lattice

Physical Review B

Download

Calorimetric evidence for two phase transitions in Ba1-xKxFe2As2 with fermion pairing and quadrupling states

Download

Possible time-reversal-symmetry-breaking fermionic quadrupling condensate in twisted bilayer graphene

arXiv (Cornell University), Jun 6, 2022

$Research paper thumbnail of Calorimetric evidence for two phase transitions in Ba$_{\rm 1-x}$K$_{\rm x}$Fe$_{2}$As$_{2}$ with fermion pairing and quadrupling states$

Calorimetric evidence for two phase transitions in Ba$_{\rm 1-x}$K$_{\rm x}$Fe$_{2}$As$_{2}$ with fermion pairing and quadrupling states

arXiv (Cornell University), Dec 27, 2022

Download

Prediction of time-reversal-symmetry breaking fermionic quadrupling condensate in twisted bilayer graphene

Physical Review B

Download

Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component London models

Physical Review B

Download

Interplay of spin waves and vortices in the 2D XY model at small vortex-core energy

Download

Finite-Frequency Dissipation in Two-Dimensional Superconductors with Disorder at the Nanoscale