Title: Large Magnetic Gap in a Designer Ferromagnet–Topological Insulator–Ferromagnet Heterostructure

Abstract

Abstract Combining magnetism and nontrivial band topology gives rise to quantum anomalous Hall (QAH) insulators and exotic quantum phases such as the QAH effect where current flows without dissipation along quantized edge states. Inducing magnetic order in topological insulators via proximity to a magnetic material offers a promising pathway toward achieving the QAH effect at a high temperature for lossless transport applications. One promising architecture involves a sandwich structure comprising two single‐septuple layers (1SL) of MnBi ₂ Te ₄ (a 2D ferromagnetic insulator) with ultrathin few quintuple layer (QL) Bi ₂ Te ₃ in the middle, and it is predicted to yield a robust QAH insulator phase with a large bandgap greater than 50 meV. Here, the growth of a 1SL MnBi ₂ Te ₄ /4QL Bi ₂ Te ₃ /1SL MnBi ₂ Te ₄ heterostructure via molecular beam epitaxy is demonstrated and the electronic structure probed using angle‐resolved photoelectron spectroscopy. Strong hexagonally warped massive Dirac fermions and a bandgap of 75 ± 15 meV are observed. The magnetic origin of the gap is confirmed by the observation of the exchange‐Rashba effect, as well as the vanishing bandgap above the Curie temperature, in agreement with density functional theory calculations. Thesemore » findings provide insights into magnetic proximity effects in topological insulators and reveal a promising platform for realizing the QAH effect at elevated temperatures.« less

Authors:

Li, Qile ^[1]; Trang, Chi Xuan ^[2]; Wu, Weikang ^[3]; Hwang, Jinwoong ^[4]; Cortie, David ^[5]; Medhekar, Nikhil ^[6]; Mo, Sung‐Kwan ^[4]; Yang, Shengyuan A. ^[7]; Edmonds, Mark T.  ^[2]

• Search DOE PAGES for author "Edmonds, Mark T."
• Search DOE PAGES for ORCID "0000-0001-8054-5470"

---

+ Show Author Affiliations

1. School of Physics and Astronomy Monash University Clayton VIC 3800 Australia, ARC Centre for Future Low Energy Electronics Technologies Monash University Clayton VIC 3800 Australia, Department of Materials Science and Engineering Monash University Clayton VIC 3800 Australia
2. School of Physics and Astronomy Monash University Clayton VIC 3800 Australia, ARC Centre for Future Low Energy Electronics Technologies Monash University Clayton VIC 3800 Australia
3. Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore 487372 Singapore, Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore
4. Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
5. Australian Nuclear Science and Technology Organization Lucas Heights NSW 2234 Australia, Institute for Superconductivity and Electronic Materials University of Wollongong Wollongong NSW 2522 Australia
6. ARC Centre for Future Low Energy Electronics Technologies Monash University Clayton VIC 3800 Australia, Department of Materials Science and Engineering Monash University Clayton VIC 3800 Australia
7. Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore 487372 Singapore

Publication Date:

Thu Mar 31 00:00:00 EDT 2022

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; Australian Research Council (ARC); Singapore Ministry of Education

OSTI Identifier:

1860440

Alternate Identifier(s):

OSTI ID: 1860441; OSTI ID: 1884552

Grant/Contract Number:  

AC02-05CH11231; 180100314; MOE2019-T2-1-001; CE170100039

Resource Type:

Published Article

Journal Name:

Advanced Materials

Additional Journal Information:

Journal Name: Advanced Materials Journal Volume: 34 Journal Issue: 21; Journal ID: ISSN 0935-9648

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

Germany

Language:

English

Subject:

36 MATERIALS SCIENCE