Pressure-Tuned Intralayer Exchange in Superlattice-Like MnBi2Te4/(Bi2Te3) n Topological Insulators

Jifeng Shao; Yuntian Liu; Meng Zeng; Jingyuan Li; Xuefeng Wu; Xiao-Ming Ma; Feng Jin; Ruie Lu; Yichen Sun; Mingqiang Gu; Kedong Wang; Wenbin Wu; Liusuo Wu; Chang Liu; Qihang Liu; Yue Zhao

doi:10.1021/acs.nanolett.1c01874

Pressure-Tuned Intralayer Exchange in Superlattice-Like MnBi₂Te₄/(Bi₂Te₃) _n Topological Insulators

Nano Lett. 2021 Jul 14;21(13):5874-5880. doi: 10.1021/acs.nanolett.1c01874. Epub 2021 Jul 1.

Authors

Jifeng Shao¹, Yuntian Liu¹, Meng Zeng¹, Jingyuan Li¹, Xuefeng Wu¹, Xiao-Ming Ma¹, Feng Jin², Ruie Lu¹, Yichen Sun¹, Mingqiang Gu¹, Kedong Wang¹, Wenbin Wu², Liusuo Wu¹, Chang Liu¹, Qihang Liu^{1

3

4}, Yue Zhao¹

Affiliations

¹ Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
² Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China.
³ Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, China.
⁴ Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China.

PMID: 34197120
DOI: 10.1021/acs.nanolett.1c01874

Abstract

The magnetic structures of MnBi₂Te₄(Bi₂Te₃)_n can be manipulated by tuning the interlayer coupling via the number of Bi₂Te₃ spacer layers n, while the intralayer ferromagnetic (FM) exchange coupling is considered too robust to control. By applying hydrostatic pressure up to 3.5 GPa, we discover opposite responses of magnetic properties for n = 1 and 2. MnBi₄Te₇ stays at A-type antiferromagnetic (AFM) phase with a decreasing Néel temperature and an increasing saturation field. In sharp contrast, MnBi₆Te₁₀ experiences a phase transition from A-type AFM to a quasi-two-dimensional FM state with a suppressed saturation field under pressure. First-principles calculations reveal the essential role of intralayer exchange coupling from lattice compression in determining these magnetic properties. Such magnetic phase transition is also observed in 20% Sb-doped MnBi₆Te₁₀ because of the in-plane lattice compression.

Keywords: first-principles calculations; hydrostatic pressure; intralayer exchange coupling; magnetic topological insulator; quasi-two-dimensional ferromagnetic state.