Title: Role of Magnetic Defects in Tuning Ground States of Magnetic Topological Insulators

Abstract

Magnetic defects play an important, but poorly understood, role in magnetic topological insulators (TIs). For example, topological surface transport and bulk magnetic properties are controlled by magnetic defects in Bi₂Se₃-based dilute ferromagnetic (FM) TIs and MnBi₂Te₄ (MBT)-based antiferromagnetic (AFM) TIs. Despite its nascent ferromagnetism, our inelastic neutron scattering data show that a fraction of the Mn defects in Sb₂Te₃ form strong AFM dimer singlets within a quintuple block. The AFM superexchange coupling occurs via Mn-Te-Mn linear bonds and is identical to the AFM coupling between antisite defects and the FM Mn layer in MBT, establishing common interactions in the two materials classes. It is also found that the FM correlations in (Sb_{1 – x}Mn_x)₂Te₃ are likely driven by magnetic defects in adjacent quintuple blocks across the van der Waals gap. In addition to providing answers to long-standing questions about the evolution of FM order in dilute TI, these results also show that the evolution of global magnetic order from AFM to FM in Sb-substituted MBT is controlled by defect engineering of the intrablock and interblock coupling.

Authors:

Islam, Farhan  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6249-0779"

Lee, Yongbin ^[2]; Pajerowski, Daniel M.  ^[3];

• Search DOE PAGES for author "Pajerowski, Daniel M."
• Search DOE PAGES for ORCID "0000-0003-3890-2379"

Oh, JinSu ^[2]; Tian, Wei ^[3]; Zhou, Lin  ^[4];

• Search DOE PAGES for author "Zhou, Lin"
• Search DOE PAGES for ORCID "0000-0003-2286-6510"

Yan, Jiaqiang  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-6625-4706"

Ke, Liqin  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-5130-9006"

McQueeney, Robert J.  ^[1];

• Search DOE PAGES for author "McQueeney, Robert J."
• Search DOE PAGES for ORCID "0000-0003-0718-5602"

Vaknin, David  ^[1]

• Search DOE PAGES for author "Vaknin, David"
• Search DOE PAGES for ORCID "0000-0002-0899-9248"

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+ Show Author Affiliations

1. Division of Materials Sciences and Engineering Ames National Laboratory Ames IA 50011 USA, Department of Physics and Astronomy Iowa State University Ames IA 50011 USA
2. Division of Materials Sciences and Engineering Ames National Laboratory Ames IA 50011 USA
3. Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
4. Division of Materials Sciences and Engineering Ames National Laboratory Ames IA 50011 USA, Department of Materials Science and Engineering Iowa State University Ames IA 50011 USA
5. Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA

Publication Date:

Thu Mar 16 00:00:00 EDT 2023

Research Org.:

Ames Laboratory (AMES), Ames, IA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division

OSTI Identifier:

1962139

Alternate Identifier(s):

OSTI ID: 1923461; OSTI ID: 1975299; OSTI ID: 1986202

Report Number(s):

IS-J-10,995
Journal ID: ISSN 0935-9648; 2209951

Grant/Contract Number:  

AC02-07CH11358; AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Advanced Materials

Additional Journal Information:

Journal Name: Advanced Materials Journal Volume: 35 Journal Issue: 21; Journal ID: ISSN 0935-9648

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

Germany

Language:

English

Subject:

36 MATERIALS SCIENCE; ferromagnetic correlation; localized dimer formation; magnetic inelastic neutron scattering; magnetic topological insulators