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Title: Disconnected elementary band representations, fragile topology, and Wilson loops as topological indices: An example on the triangular lattice

Abstract

In this study, we examine the topological phases that can arise in triangular lattices with disconnected elementary band representations. We show that, although these phases may be “fragile” with respect to the addition of extra bands, their topological properties are manifest in certain nontrivial holonomies (Wilson loops) in the space of nontrivial bands. We introduce an eigenvalue index for fragile topology, and we show how a nontrivial value of this index manifests as the winding of a hexagonal Wilson loop; this remains true even in the absence of time-reversal or sixfold rotational symmetry. Additionally, when time-reversal and twofold rotational symmetry are present, we show directly that there is a protected nontrivial winding in more conventional Wilson loops. Crucially, we emphasize that these Wilson loops cannot change without closing a gap to the nontrivial bands. By studying the entanglement spectrum for the fragile bands, we comment on the relationship between fragile topology and the “obstructed atomic limit” of Bradlyn et al. [Nature (London) 547, 298 (2017)]. We conclude with some perspectives on topological matter beyond the K-theory classification.

Authors:
 [1];  [2];  [3];  [4]
  1. Univ. of Illinois at Urbana-Champaign, IL (United States); Donostia International Physics Center (Spain)
  2. Chinese Academy of Sciences (CAS), Beijing (China); Princeton Univ., NJ (United States)
  3. Stony Brook Univ., NY (United States); Flatiron Institute, New York, NY (United States)
  4. Princeton Univ., NJ (United States); Freie Univ. Berlin (Germany); Max Planck Inst. of Microstructure Physics, Halle (Germany)
Publication Date:
Research Org.:
Princeton Univ., NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
OSTI Identifier:
1612431
Alternate Identifier(s):
OSTI ID: 1492107
Grant/Contract Number:  
SC0016239
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review. B
Additional Journal Information:
Journal Volume: 99; Journal Issue: 4; 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; Materials Science; Physics; Topological phases of matter; Topological materials Band structure methods; Symmetries in condensed matter

Citation Formats

Bradlyn, Barry, Wang, Zhijun, Cano, Jennifer, and Bernevig, B. Andrei. Disconnected elementary band representations, fragile topology, and Wilson loops as topological indices: An example on the triangular lattice. United States: N. p., 2019. Web. doi:10.1103/physrevb.99.045140.
Bradlyn, Barry, Wang, Zhijun, Cano, Jennifer, & Bernevig, B. Andrei. Disconnected elementary band representations, fragile topology, and Wilson loops as topological indices: An example on the triangular lattice. United States. https://doi.org/10.1103/physrevb.99.045140
Bradlyn, Barry, Wang, Zhijun, Cano, Jennifer, and Bernevig, B. Andrei. Fri . "Disconnected elementary band representations, fragile topology, and Wilson loops as topological indices: An example on the triangular lattice". United States. https://doi.org/10.1103/physrevb.99.045140. https://www.osti.gov/servlets/purl/1612431.
@article{osti_1612431,
title = {Disconnected elementary band representations, fragile topology, and Wilson loops as topological indices: An example on the triangular lattice},
author = {Bradlyn, Barry and Wang, Zhijun and Cano, Jennifer and Bernevig, B. Andrei},
abstractNote = {In this study, we examine the topological phases that can arise in triangular lattices with disconnected elementary band representations. We show that, although these phases may be “fragile” with respect to the addition of extra bands, their topological properties are manifest in certain nontrivial holonomies (Wilson loops) in the space of nontrivial bands. We introduce an eigenvalue index for fragile topology, and we show how a nontrivial value of this index manifests as the winding of a hexagonal Wilson loop; this remains true even in the absence of time-reversal or sixfold rotational symmetry. Additionally, when time-reversal and twofold rotational symmetry are present, we show directly that there is a protected nontrivial winding in more conventional Wilson loops. Crucially, we emphasize that these Wilson loops cannot change without closing a gap to the nontrivial bands. By studying the entanglement spectrum for the fragile bands, we comment on the relationship between fragile topology and the “obstructed atomic limit” of Bradlyn et al. [Nature (London) 547, 298 (2017)]. We conclude with some perspectives on topological matter beyond the K-theory classification.},
doi = {10.1103/physrevb.99.045140},
journal = {Physical Review. B},
number = 4,
volume = 99,
place = {United States},
year = {Fri Jan 25 00:00:00 EST 2019},
month = {Fri Jan 25 00:00:00 EST 2019}
}

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Works referenced in this record:

Fragile Topology and Wannier Obstructions
journal, September 2018


Twisted Equivariant Matter
journal, March 2013


Topological crystalline materials: General formulation, module structure, and wallpaper groups
journal, June 2017


Band representations and symmetry types of bands in solids
journal, March 1981


Symmetry Specification of Bands in Solids
journal, September 1980


Symmetry-based indicators of band topology in the 230 space groups
journal, June 2017


Topological Classification of Crystalline Insulators through Band Structure Combinatorics
journal, December 2017


Graph theory data for topological quantum chemistry
journal, August 2017


No-go theorem for topological insulators and high-throughput identification of Chern insulators
journal, November 2018


Topological Insulators from Group Cohomology
journal, April 2016


Wannier representation of Z 2 topological insulators
journal, January 2011


Spin-Orbit-Free Topological Insulators without Time-Reversal Symmetry
journal, September 2014


Double crystallographic groups and their representations on the Bilbao Crystallographic Server
journal, September 2017

  • Elcoro, Luis; Bradlyn, Barry; Wang, Zhijun
  • Journal of Applied Crystallography, Vol. 50, Issue 5
  • DOI: 10.1107/S1600576717011712

Quantum Spin Hall Effect in Graphene
journal, November 2005


Higher-order topology in bismuth
journal, July 2018


Bulk topological invariants in noninteracting point group symmetric insulators
journal, September 2012


Topological Bloch oscillations
journal, July 2018


Quantitative mappings between symmetry and topology in solids
journal, August 2018


Relating the entanglement spectrum of noninteracting band insulators to their quantum geometry and topology
journal, September 2013


On the Non‐Orthogonality Problem Connected with the Use of Atomic Wave Functions in the Theory of Molecules and Crystals
journal, March 1950

  • Löwdin, Per‐Olov
  • The Journal of Chemical Physics, Vol. 18, Issue 3
  • DOI: 10.1063/1.1747632

Topological quantum chemistry
journal, July 2017

  • Bradlyn, Barry; Elcoro, L.; Cano, Jennifer
  • Nature, Vol. 547, Issue 7663
  • DOI: 10.1038/nature23268

Higher-order topology in bismuth
text, January 2018

  • Schindler, Frank; Wang, Zhijun; Vergniory, Maia G.
  • Nature Publishing Group
  • DOI: 10.5167/uzh-158533

Bulk Topological Invariants in Noninteracting Point Group Symmetric Insulators
text, January 2012


Symmetry-based Indicators of Band Topology in the 230 Space Groups
text, January 2017


Topological Bloch oscillations
text, January 2017


Fragile Topology and Wannier Obstructions
text, January 2017


Topology of Disconnected Elementary Band Representations
text, January 2017


Quantitative mappings between symmetry and topology in solids
text, January 2017


Works referencing / citing this record:

Tutorial: Computing Topological Invariants in 2D Photonic Crystals
journal, October 2019

  • Blanco de Paz, María; Devescovi, Chiara; Giedke, Geza
  • Advanced Quantum Technologies, Vol. 3, Issue 2
  • DOI: 10.1002/qute.201900117

Strange topological materials are popping up everywhere physicists look
journal, July 2019


A complete catalogue of high-quality topological materials
journal, February 2019


Band topology in classical waves: Wilson-loop approach to topological numbers and fragile topology
journal, September 2019


Stiefel–Whitney classes and topological phases in band theory
journal, October 2019


Landau quantization of nearly degenerate bands and full symmetry classification of Landau level crossings
journal, July 2019


Classification of crystalline insulators without symmetry indicators: Atomic and fragile topological phases in twofold rotation symmetric systems
journal, September 2019


Diagnosis of topological nodal lines with nontrivial monopole charge in the presence of rotation symmetries
journal, November 2019


Fragile topology protected by inversion symmetry: Diagnosis, bulk-boundary correspondence, and Wilson loop
journal, November 2019


Fractional disclination charge in two-dimensional C n -symmetric topological crystalline insulators
journal, March 2020


Fragile topological phases in interacting systems
journal, March 2019


Symmetry representation approach to topological invariants in C 2 z T -symmetric systems
journal, June 2019


Quantization of fractional corner charge in C n -symmetric higher-order topological crystalline insulators
journal, June 2019


Fractional corner charges in spin-orbit coupled crystals
journal, November 2019


Fragile topologically protected perfect reflection for acoustic waves
journal, February 2020


Twisted bulk-boundary correspondence of fragile topology
journal, February 2020


Strong and fragile topological Dirac semimetals with higher-order Fermi arcs
text, January 2020


Strong and fragile topological Dirac semimetals with higher-order Fermi arcs
journal, January 2020


Fractional corner charges in spin-orbit coupled crystals
text, January 2019

  • Schindler, Frank; Brzezińska, Marta; Benalcazar, Wladimir A.
  • American Physical Society
  • DOI: 10.5167/uzh-179205

Fragile topological phases in interacting systems
text, January 2018


Stiefel-Whitney classes and topological phases in band theory
text, January 2019


Fractional disclination charge in two-dimensional $C_n-$symmetric topological crystalline insulators
text, January 2019


Fractional corner charges in spin-orbit coupled crystals
text, January 2019


Strong and Fragile Topological Dirac Semimetals with Higher-Order Fermi Arcs
text, January 2019


A fractional corner anomaly reveals higher-order topology
journal, June 2020

  • Peterson, Christopher W.; Li, Tianhe; Benalcazar, Wladimir A.
  • Science, Vol. 368, Issue 6495
  • DOI: 10.1126/science.aba7604

IrRep: Symmetry eigenvalues and irreducible representations of ab initio band structures
text, January 2022