The electronic structure of Mn_1-xPb_xBi₂Te₄: experimental evidence of topological phase transition

2024/11/15 by D. A. Estyunin, T. P. Estyunina, Estyunin, D. A. +31
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Phase-change materials and chalcogenides #Topological Materials and Phenomena

paper · pdf · doi:10.48550/arxiv.2411.10390

openalex publication_date 2024/11/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

This study investigates methods for controlling the physical properties of the intrinsic magnetic topological insulator MnBi₂Te₄ (MBT) by substituting Mn with Pb in Mn_1-xPb_xBi₂Te₄ (MPBT) solid solutions. This substitution enables tunable magnetic and electronic properties. Using various angle-resolved photoemission spectroscopy (ARPES) techniques, including spin-resolved and circular dichroism (CD) measurements, we analyzed the evolution of the electronic structure across different Pb concentrations, with a focus on topological phase transitions (TPT) near x = 50 %. Key indicators of TPT include the presence or absence of topological surface states (TSS) and bulk band gap closure. The results show a gradual decrease of the bulk band gap in the electronic structure of MPBT up to x = 40 %, where it nearly vanishes, followed by a constant gap value between 40 - 60 %, and its reopening above 80 %, which is accompanied by a transition of the electronic structure of MPBT to a PbBi₂Te₄-like electronic structure. TSS were observed at x less than 30 % and greater than 80 %, as confirmed by CD and spin-resolved ARPES data, but were absent near x = 55 %, suggesting a distinct topological phase - possibly semi-metallic or a trivial insulator with a narrow gap phase. These findings demonstrate the tunability of the electronic structure of MPBT, making it a promising candidate for topological and spintronic applications.

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