Subtle metastability of the layered magnetic topological insulator MnBi2Te4 from weak interactions
| Autor: | Jianwei Sun, Yu Wang, Jamin Kidd, Jinliang Ning, Zhiqiang Mao, Yanglin Zhu, Yingdong Guan |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Degrees of freedom (physics and chemistry)
FOS: Physical sciences 02 engineering and technology 01 natural sciences symbols.namesake Metastability 0103 physical sciences lcsh:TA401-492 General Materials Science 010306 general physics Quantum Topology (chemistry) Spin-½ lcsh:Computer software Physics Condensed Matter - Materials Science Condensed matter physics Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Computer Science Applications lcsh:QA76.75-76.765 Mechanics of Materials Modeling and Simulation Helmholtz free energy Topological insulator symbols lcsh:Materials of engineering and construction. Mechanics of materials van der Waals force 0210 nano-technology |
| Zdroj: | npj Computational Materials, Vol 6, Iss 1, Pp 1-6 (2020) |
| DOI: | 10.48550/arxiv.1912.01173 |
| Popis: | Layered quantum materials can host interesting properties, including magnetic and topological, for which enormous computational predictions have been done. Their thermodynamic stability is much less visited computationally, which however determines the existence of materials and can be used to guide experimental synthesis. MnBi2Te4 is one of such layered quantum materials that was predicted to be an intrinsic antiferromagnetic topological insulator, and later experimentally realized but in a thermodynamically metastable state. Here, using a combined first-principles-based approach that considers lattice, charge, and spin degrees of freedom, we investigate the metastability of MnBi2Te4 by calculating the Helmholtz free energy for the reaction Bi2Te3 + MnTe → MnBi2Te4. We identify a temperature range (~500–873 K) in which the compound is stable with respect to the competing binary phases, consistent with experimental observation. We validate the predictions by comparing the calculated specific heats contributed from different degrees of freedom with experimental results. Our findings indicate that the degrees of freedom responsible for the van der Waals interaction, lattice vibration, magnetic coupling, and nontrivial band topology in MnBi2Te4 not only enable emergent phenomena but also play a crucial role in determining its thermodynamic stability. This conclusion lays the foundation for the future computational material synthesis of novel layered systems. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|