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Title: Competing phases of interacting electrons on triangular lattices in moiré heterostructures

Abstract

We study the quantum many-body instabilities of interacting electrons with SU(2) × SU(2) symmetry in spin and orbital degrees of freedom on the triangular lattice near van-Hove filling. Our work is motivated by effective models for the flat bands in hexagonal moiré heterostructures like twisted bilayer boron nitride and trilayer graphene-boron nitride systems. We consider an extended Hubbard model including onsite Hubbard and Hund's couplings, as well as nearest-neighbor exchange interactions, and analyze the different ordering tendencies with the help of an unbiased functional renormalization group approach. We find three classes of instabilities controlled by the filling and bare interactions. For a nested Fermi surface at van-Hove filling, Hund-like couplings induce a weak instability towards spin or orbital density wave phases. An SU(4) exchange interaction moves the system towards a Chern insulator, which is robust with respect to perturbations from Hund-like interactions or deviations from perfect nesting. Further, in an extended range of fillings and interactions, we find topological d ± id and (spin-singlet)-(orbital-singlet) f-wave superconductivity.

Authors:
ORCiD logo [1];  [2];  [3]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. RWTH Aachen Univ., and JARA Fundamentals of Future Information Technology (Germany)
  3. Univ. of Cologne, Cologne (Germany)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1524562
Alternate Identifier(s):
OSTI ID: 1511893
Report Number(s):
BNL-211746-2019-JAAM
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
SC0012704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 99; 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

Classen, Laura, Honerkamp, Carsten, and Scherer, Michael M. Competing phases of interacting electrons on triangular lattices in moiré heterostructures. United States: N. p., 2019. Web. doi:10.1103/PhysRevB.99.195120.
Classen, Laura, Honerkamp, Carsten, & Scherer, Michael M. Competing phases of interacting electrons on triangular lattices in moiré heterostructures. United States. https://doi.org/10.1103/PhysRevB.99.195120
Classen, Laura, Honerkamp, Carsten, and Scherer, Michael M. Fri . "Competing phases of interacting electrons on triangular lattices in moiré heterostructures". United States. https://doi.org/10.1103/PhysRevB.99.195120. https://www.osti.gov/servlets/purl/1524562.
@article{osti_1524562,
title = {Competing phases of interacting electrons on triangular lattices in moiré heterostructures},
author = {Classen, Laura and Honerkamp, Carsten and Scherer, Michael M.},
abstractNote = {We study the quantum many-body instabilities of interacting electrons with SU(2) × SU(2) symmetry in spin and orbital degrees of freedom on the triangular lattice near van-Hove filling. Our work is motivated by effective models for the flat bands in hexagonal moiré heterostructures like twisted bilayer boron nitride and trilayer graphene-boron nitride systems. We consider an extended Hubbard model including onsite Hubbard and Hund's couplings, as well as nearest-neighbor exchange interactions, and analyze the different ordering tendencies with the help of an unbiased functional renormalization group approach. We find three classes of instabilities controlled by the filling and bare interactions. For a nested Fermi surface at van-Hove filling, Hund-like couplings induce a weak instability towards spin or orbital density wave phases. An SU(4) exchange interaction moves the system towards a Chern insulator, which is robust with respect to perturbations from Hund-like interactions or deviations from perfect nesting. Further, in an extended range of fillings and interactions, we find topological d ± id and (spin-singlet)-(orbital-singlet) f-wave superconductivity.},
doi = {10.1103/PhysRevB.99.195120},
url = {https://www.osti.gov/biblio/1524562}, journal = {Physical Review B},
issn = {2469-9950},
number = 19,
volume = 99,
place = {United States},
year = {2019},
month = {5}
}

Journal Article:

Citation Metrics:
Cited by: 11 works
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Works referenced in this record:

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    Works referencing / citing this record:

    Cold atoms in twisted-bilayer optical potentials
    journal, November 2019


    Spin-valley density wave in moiré materials
    journal, July 2019


    Chiral twist on the high- T c phase diagram in moiré heterostructures
    journal, August 2019


    Superconductor versus insulator in twisted bilayer graphene
    journal, September 2019


    Inherited and flatband-induced ordering in twisted graphene bilayers
    journal, October 2019


    Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
    journal, February 2020


    Valley Jahn-Teller Effect in Twisted Bilayer Graphene
    journal, October 2019


    Ground state superconducting pair correlations in twisted bilayer graphene
    journal, December 2019