The bulk-corner correspondence of time-reversal symmetric insulators

Sander Kooi, Guido van Miert, Carmine Ortix

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The topology of insulators is usually revealed through the presence of gapless boundary modes: this is the so-called bulk-boundary correspondence. However, the many-body wavefunction of a crystalline insulator is endowed with additional topological properties that do not yield surface spectral features, but manifest themselves as (fractional) quantized electronic charges localized at the crystal boundaries. Here, we formulate such bulk-corner correspondence for the physical relevant case of materials with time-reversal symmetry and spin-orbit coupling. To do so we develop partial real-space invariants that can be neither expressed in terms of Berry phases nor using symmetry-based indicators. These previously unknown crystalline invariants govern the (fractional) quantized corner charges both of isolated material structures and of heterostructures without gapless interface modes. We also show that the partial real-space invariants are able to detect all time-reversal symmetric topological phases of the recently discovered fragile type.

Original languageEnglish
Article number1
Number of pages12
Journalnpj Quantum Materials
Volume6
DOIs
Publication statusPublished - 4 Jan 2021

Fingerprint

Dive into the research topics of 'The bulk-corner correspondence of time-reversal symmetric insulators'. Together they form a unique fingerprint.

Cite this