Emergence of - s , - p - d band inversion in zincblende gold iodide topological insulator and its thermoelectric properties.

Autor: Sattigeri RM; Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390002, India., Gajaria TK; Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390002, India., Jha PK; Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390002, India., Śpiewak P; Materials Design Division, Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Wołoska Str., 02-507 Warsaw, Poland., Kurzydłowski KJ; Materials Design Division, Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Wołoska Str., 02-507 Warsaw, Poland.; Faculty of Mechanical Engineering, Bialystok University of Technology, 45C Wiejska Str., 15-351, Bialystok, Poland.
Jazyk: angličtina
Zdroj: Journal of physics. Condensed matter : an Institute of Physics journal [J Phys Condens Matter] 2021 Feb 19; Vol. 33 (15). Date of Electronic Publication: 2021 Feb 19.
DOI: 10.1088/1361-648X/abdce8
Abstrakt: We employ first-principles calculations to investigate the topological states (TS) and thermoelectric (TE) transport properties of three dimensional (3D) gold iodide (AuI) which belongs to the zincblende family. We explore, semi-metal (SM) to topological conductor (TC) and topological insulator (TI) phase transitions. Under pristine conditions, AuI exhibits Dirac SM nature but, under the influence of mild isotropic compressive pressure the system undergoes electronic quantum phase transition driving it into non-trivial topological state. This state exhibits Dresselhaus like band spin splitting leading to a TC state. In order to realize TI state from the SM state, we break the cubic symmetry of the system by introducing a compressive pressure along (001) crystal direction. The non-trivial TI nature of the system is characterized by the emergence of robust surface states and theZ2invariant ν 0 = 1 which indicates a strong TI nature. A novel facet of the phase transition discussed here is, the - s and - p , - d orbital band inversion mechanism which is unconventional as compared to previously explored TI families. This mechanism unravels new path by which TI materials can be predicted. Also, we investigated the lattice and electronic contributions to the TE transport properties. We characterize the TE performance by calculating the figure of merit (zT) and find that, at room temperature (300 K) and for a fixed doping concentration (i.e., n = 1 × 10 19  cm -3 ) the zT is 0.55 and 0.53 for electrons and holes respectively. This is quite remarkable since, higher values of zT are generally predicted at higher temperature scales whereas, zT values as in the present case are desired at room temperatures for various energy applications. The manifestation of non-trivial TS governed by the unconventional band inversion mechanism and the TE properties of AuI make it a unique multi-functional candidate with probable thermoelectric and spintronic applications.
(© 2021 IOP Publishing Ltd.)
Databáze: MEDLINE
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