Maiti, A and Pandeya, RP and Singh, B and Iyer, KK and Thamizhavel, A and Maiti, K (2021) Anomalies in the temperature evolution of Dirac states in the topological crystalline insulator SnTe. In: Physical Review B, 104 (19).
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Abstract
Discovery of topologically protected surface states, believed to be immune to weak disorder and thermal effects, opened up a new avenue to reveal exotic fundamental science and advanced technology. While time-reversal symmetry plays the key role in most such materials, the bulk crystalline symmetries such as mirror symmetry preserve the topological properties of topological crystalline insulators (TCIs). It is apparent that any structural change may alter the topological properties of TCIs. To investigate this relatively unexplored landscape, we study the temperature evolution of Dirac fermion states in an archetypical mirror-symmetry protected TCI, SnTe, employing high-resolution angle-resolved photoemission spectroscopy and density functional theory studies. Experimental results reveal a perplexing scenario: the bulk bands observed at 22 K move nearer to the Fermi level at 60 K and again shift back to higher binding energies at 120 K. The slope of the surface Dirac bands at 22 K becomes smaller at 60 K and changes back to a larger value at 120 K. Our results from the first-principles calculations suggest that these anomalies can be attributed to the evolution of the hybridization physics with complex structural changes induced by temperature. In addition, we discover drastically reduced intensity of the Dirac states at the Fermi level at high temperatures may be due to complex evolution of anharmonicity, strain, etc. These results address the robustness of the topologically protected surface states due to thermal effects and emphasize the importance of covalency and anharmonicity in the topological properties of such emerging quantum materials. © 2021 American Physical Society.
| Item Type: | Journal Article |
|---|---|
| Publication: | Physical Review B |
| Publisher: | American Physical Society |
| Additional Information: | The copyright for this article belongs to Authors |
| Keywords: | Binding energy; Calculations; Density functional theory; Fermi level; IV-VI semiconductors; Mirrors; Photoelectron spectroscopy; Quantum chemistry; Quantum theory; Surface states; Tin compounds, Advanced technology; Anharmonicities; Bulk crystalline; Crystalline insulators; Mirror symmetry; Science technologies; Temperature evolution; Time reversal symmetries; Topological properties; Weak disorder, Topology |
| Department/Centre: | UG Programme |
| Date Deposited: | 03 Dec 2021 08:45 |
| Last Modified: | 03 Dec 2021 08:45 |
| URI: | http://eprints.iisc.ac.in/id/eprint/70610 |
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