Edge currents as probe of topology in twisted cuprate bilayers

Fuente: arXiv
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Main Authors: Pathak, Vedangi, Can, Oguzhan, Franz, Marcel
Format: Preprint
Published: 2024
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author Pathak, Vedangi
Can, Oguzhan
Franz, Marcel
author_facet Pathak, Vedangi
Can, Oguzhan
Franz, Marcel
contents Bilayers made of high-$T_c$ cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ assembled with a twist angle close to $45^\circ$ have been recently shown to spontaneously break time reversal symmetry $\mathcal{T}$, consistent with theoretical predictions for emergent chiral topological $d_{x^2-y^2}+id_{xy}$ phase in such twisted $d$-wave superconductors. Here we use a minimal microscopic model to estimate the size of spontaneous chiral edge currents expected to occur in the $\mathcal{T}$-broken phase. In accord with previous theoretical studies of chiral $d$-wave superconductors we find small but non-vanishing edge currents which we nevertheless predict to be above the detection threshold of the state-of-the-art magnetic scanning probe microscopy. In addition, by deriving a simple relation between the edge current and the electron spectral function we help elucidate the longstanding disparity between the size of edge currents in chiral $d$-wave and $p$-wave superconductors.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14851
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Edge currents as probe of topology in twisted cuprate bilayers
Pathak, Vedangi
Can, Oguzhan
Franz, Marcel
Superconductivity
Strongly Correlated Electrons
Bilayers made of high-$T_c$ cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ assembled with a twist angle close to $45^\circ$ have been recently shown to spontaneously break time reversal symmetry $\mathcal{T}$, consistent with theoretical predictions for emergent chiral topological $d_{x^2-y^2}+id_{xy}$ phase in such twisted $d$-wave superconductors. Here we use a minimal microscopic model to estimate the size of spontaneous chiral edge currents expected to occur in the $\mathcal{T}$-broken phase. In accord with previous theoretical studies of chiral $d$-wave superconductors we find small but non-vanishing edge currents which we nevertheless predict to be above the detection threshold of the state-of-the-art magnetic scanning probe microscopy. In addition, by deriving a simple relation between the edge current and the electron spectral function we help elucidate the longstanding disparity between the size of edge currents in chiral $d$-wave and $p$-wave superconductors.
title Edge currents as probe of topology in twisted cuprate bilayers
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2403.14851