Structural and topological phase transitions in Se doping-controlled intrinsic magnetic topological material FeBi2Te4

Defects profoundly affect the magnetic, electronic structure and topological behaviour of intrinsic magnetic topological insulators. Here, we investigate the magnetic, structural stability and topological properties of different Te atomic sites in the intrinsic magnetic topological insulator FeBi2Te...

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Bibliographic Details
Published in:New journal of physics 2023-09, Vol.25 (9), p.093004
Main Authors: Guo, Wen-Ti, Huang, Zhigao, Zhang, Jian-Min
Format: Article
Language:English
Subjects:
Bismuth
Chemical bonds
Defects
Electronegativity
Electronic structure
FeBi
FeBi2Te4
Free energy
Heat of formation
Lattice parameters
Magnetic moments
Magnetic properties
magnetic topological insulator
Metalloids
Phase transitions
Physics
Structural stability
substitute defects
Substitutes
Tellurium
Topological insulators
topological phase transition
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Summary:Defects profoundly affect the magnetic, electronic structure and topological behaviour of intrinsic magnetic topological insulators. Here, we investigate the magnetic, structural stability and topological properties of different Te atomic sites in the intrinsic magnetic topological insulator FeBi2Te4 with Se substitution of the FM-z magnetic order. When Se replaces the outermost site of the septuple layer (the Te atomic layer connected by van der Waals bonds), the Se–Bi bond length formed with its nearest neighbour Bi is drastically shortened and the lattice constant and volume contract accordingly. We speculate that this defect-induced chemical bond enhancement is related to the strong electronegativity of Se over Te. In contrast, the system has lower formation energy, a more stable structure, and enhanced magnetic moment when Se replaces the Te atomic layer inside the septuple layer. Also, we reveal a variety of topological phase transitions due to substitution defects. FeBi2Te4 is considered to belong to the z2×z4 topological classification of higher-order topological insulators with z4 = 2. The system after Se substitution can be transformed into Weyl semimetals, strong 3D topological insulators, and unknown topological materials without symmetry-base indicators, respectively.
ISSN:1367-2630
DOI:10.1088/1367-2630/acf1c2