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Title: Pairing symmetry and spontaneous vortex-antivortex lattice in superconducting twisted-bilayer graphene: Bogoliubov-de Gennes approach

Abstract

Here, we study the superconducting pairing symmetry in twisted bilayer graphene by solving the Bogoliubov-de Gennes equation for all electrons in moiré supercells. With increasing the pairing potential, the system evolves from the mixed nontopological d + i d and p + i p phase to the s + p + d phase via the first-order phase transition. In the time-reversal symmetry breaking d + i d and p + i p phase, vortex and antivortex lattices accompanying spontaneous supercurrent are induced by the twist. The superconducting order parameter is nonuniform in the moiré unit cell. Nevertheless, the superconducting gap in the local density of states is identical in the unit cell. The twist-induced vortices and nontopological nature of the mixed d + i d and p + i p phase are not captured by the existing effective models. Our results suggest the importance of long-range pairing interaction for effective models.

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1495154
Alternate Identifier(s):
OSTI ID: 1480366
Report Number(s):
LA-UR-18-26090
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
89233218CNA000001; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 19; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Su, Ying, and Lin, Shizeng. Pairing symmetry and spontaneous vortex-antivortex lattice in superconducting twisted-bilayer graphene: Bogoliubov-de Gennes approach. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.98.195101.
Su, Ying, & Lin, Shizeng. Pairing symmetry and spontaneous vortex-antivortex lattice in superconducting twisted-bilayer graphene: Bogoliubov-de Gennes approach. United States. doi:10.1103/PhysRevB.98.195101.
Su, Ying, and Lin, Shizeng. Thu . "Pairing symmetry and spontaneous vortex-antivortex lattice in superconducting twisted-bilayer graphene: Bogoliubov-de Gennes approach". United States. doi:10.1103/PhysRevB.98.195101.
@article{osti_1495154,
title = {Pairing symmetry and spontaneous vortex-antivortex lattice in superconducting twisted-bilayer graphene: Bogoliubov-de Gennes approach},
author = {Su, Ying and Lin, Shizeng},
abstractNote = {Here, we study the superconducting pairing symmetry in twisted bilayer graphene by solving the Bogoliubov-de Gennes equation for all electrons in moiré supercells. With increasing the pairing potential, the system evolves from the mixed nontopological d + i d and p + i p phase to the s + p + d phase via the first-order phase transition. In the time-reversal symmetry breaking d + i d and p + i p phase, vortex and antivortex lattices accompanying spontaneous supercurrent are induced by the twist. The superconducting order parameter is nonuniform in the moiré unit cell. Nevertheless, the superconducting gap in the local density of states is identical in the unit cell. The twist-induced vortices and nontopological nature of the mixed d + i d and p + i p phase are not captured by the existing effective models. Our results suggest the importance of long-range pairing interaction for effective models.},
doi = {10.1103/PhysRevB.98.195101},
journal = {Physical Review B},
issn = {2469-9950},
number = 19,
volume = 98,
place = {United States},
year = {2018},
month = {11}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on November 1, 2019
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Cited by: 3 works
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