skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evidence for a topological excitonic insulator in InAs/GaSb bilayers

Abstract

Electron–hole pairing can occur in a dilute semimetal, transforming the system into an excitonic insulator state in which a gap spontaneously appears at the Fermi surface, analogous to a Bardeen–Cooper–Schrieffer (BCS) superconductor. Here, we report optical spectroscopic and electronic transport evidence for the formation of an excitonic insulator gap in an inverted InAs/GaSb quantum-well system at low temperatures and low electron–hole densities. Terahertz transmission spectra exhibit two absorption lines that are quantitatively consistent with predictions from the pair-breaking excitation dispersion calculated based on the BCS gap equation. Low-temperature electronic transport measurements reveal a gap of ~2 meV (or ~25 K) with a critical temperature of ~10 K in the bulk, together with quantized edge conductance, suggesting the occurrence of a topological excitonic insulator phase.

Authors:
 [1];  [1]; ORCiD logo [2];  [3];  [2];  [1];  [4]
  1. Rice Univ., Houston, TX (United States)
  2. Chinese Academy of Sciences (CAS), Beijing (China)
  3. Teledyne Scientific and Imaging, Thousand Oaks, CA (United States)
  4. Rice Univ., Houston, TX (United States); Peking Univ., Beijing (China)
Publication Date:
Research Org.:
Rice Univ., Houston, TX (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1499925
Grant/Contract Number:  
FG02-06ER46274
Resource Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE

Citation Formats

Du, Lingjie, Li, Xinwei, Lou, Wenkai, Sullivan, Gerard, Chang, Kai, Kono, Junichiro, and Du, Rui-Rui. Evidence for a topological excitonic insulator in InAs/GaSb bilayers. United States: N. p., 2017. Web. doi:10.1038/s41467-017-01988-1.
Du, Lingjie, Li, Xinwei, Lou, Wenkai, Sullivan, Gerard, Chang, Kai, Kono, Junichiro, & Du, Rui-Rui. Evidence for a topological excitonic insulator in InAs/GaSb bilayers. United States. doi:10.1038/s41467-017-01988-1.
Du, Lingjie, Li, Xinwei, Lou, Wenkai, Sullivan, Gerard, Chang, Kai, Kono, Junichiro, and Du, Rui-Rui. Thu . "Evidence for a topological excitonic insulator in InAs/GaSb bilayers". United States. doi:10.1038/s41467-017-01988-1. https://www.osti.gov/servlets/purl/1499925.
@article{osti_1499925,
title = {Evidence for a topological excitonic insulator in InAs/GaSb bilayers},
author = {Du, Lingjie and Li, Xinwei and Lou, Wenkai and Sullivan, Gerard and Chang, Kai and Kono, Junichiro and Du, Rui-Rui},
abstractNote = {Electron–hole pairing can occur in a dilute semimetal, transforming the system into an excitonic insulator state in which a gap spontaneously appears at the Fermi surface, analogous to a Bardeen–Cooper–Schrieffer (BCS) superconductor. Here, we report optical spectroscopic and electronic transport evidence for the formation of an excitonic insulator gap in an inverted InAs/GaSb quantum-well system at low temperatures and low electron–hole densities. Terahertz transmission spectra exhibit two absorption lines that are quantitatively consistent with predictions from the pair-breaking excitation dispersion calculated based on the BCS gap equation. Low-temperature electronic transport measurements reveal a gap of ~2 meV (or ~25 K) with a critical temperature of ~10 K in the bulk, together with quantized edge conductance, suggesting the occurrence of a topological excitonic insulator phase.},
doi = {10.1038/s41467-017-01988-1},
journal = {Nature Communications},
number = 1,
volume = 8,
place = {United States},
year = {2017},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 19 works
Citation information provided by
Web of Science

Save / Share: