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Title: Topological chiral superconductivity with spontaneous vortices and supercurrent in twisted bilayer graphene.

Abstract

We study d-wave superconductivity in twisted bilayer graphene and reveal phenomena that arise due to the moire superlattice. In the d-wave pairing, the relative motion (RM) of two electrons in a Cooper pair can have either d + id or d - id symmetry with opposite angular momenta. Due to the enlarged moire superlattice, the center-of-mass motion (COMM) can also carry a finite angular momentum while preserving the moire periodicity. By matching the total angular momentum, which has contributions from both the RM and the COMM, Cooper pairs with d + id and d - id RMs are intrinsically coupled in a way such that the COMM associated with one of the RMs has a spontaneous vortex-antivortex lattice configuration. Another phenomenon is that the chiral d-wave state carries spontaneous bulk circulating supercurrent. The chiral d-wave superconductors are gapped and also topological as characterized by an integer Chern number. Nematic d-wave superconductors, which could be stabilized, for example, by uniaxial strain, are gapless with point nodes.

Authors:
;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; Gordon and Betty Moore Foundation
OSTI Identifier:
1518487
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 99; Journal Issue: 19
Country of Publication:
United States
Language:
English

Citation Formats

Wu, Fengcheng, and Martin, Ivar. Topological chiral superconductivity with spontaneous vortices and supercurrent in twisted bilayer graphene.. United States: N. p., 2019. Web. doi:10.1103/PhysRevB.99.195114.
Wu, Fengcheng, & Martin, Ivar. Topological chiral superconductivity with spontaneous vortices and supercurrent in twisted bilayer graphene.. United States. doi:10.1103/PhysRevB.99.195114.
Wu, Fengcheng, and Martin, Ivar. Wed . "Topological chiral superconductivity with spontaneous vortices and supercurrent in twisted bilayer graphene.". United States. doi:10.1103/PhysRevB.99.195114.
@article{osti_1518487,
title = {Topological chiral superconductivity with spontaneous vortices and supercurrent in twisted bilayer graphene.},
author = {Wu, Fengcheng and Martin, Ivar},
abstractNote = {We study d-wave superconductivity in twisted bilayer graphene and reveal phenomena that arise due to the moire superlattice. In the d-wave pairing, the relative motion (RM) of two electrons in a Cooper pair can have either d + id or d - id symmetry with opposite angular momenta. Due to the enlarged moire superlattice, the center-of-mass motion (COMM) can also carry a finite angular momentum while preserving the moire periodicity. By matching the total angular momentum, which has contributions from both the RM and the COMM, Cooper pairs with d + id and d - id RMs are intrinsically coupled in a way such that the COMM associated with one of the RMs has a spontaneous vortex-antivortex lattice configuration. Another phenomenon is that the chiral d-wave state carries spontaneous bulk circulating supercurrent. The chiral d-wave superconductors are gapped and also topological as characterized by an integer Chern number. Nematic d-wave superconductors, which could be stabilized, for example, by uniaxial strain, are gapless with point nodes.},
doi = {10.1103/PhysRevB.99.195114},
journal = {Physical Review, B: Condensed Matter},
number = 19,
volume = 99,
place = {United States},
year = {2019},
month = {5}
}