High-pressure phase transitions of nitinol NiTi to a semiconductor with an unusual topological structure

Liu, Guangtao and Liu, Hanyu and Feng, Xiaolei and Redfern, Simon A. T. (2018) High-pressure phase transitions of nitinol NiTi to a semiconductor with an unusual topological structure. Physical Review B, 97 (14). ISSN 2469-9950 DOI https://doi.org/10.1103/PhysRevB.97.140104

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Abstract

Systematic ab initio structure simulations have been used to explore the high-pressure behavior of nitinol (NiTi) at zero temperature. Our crystal structure prediction and first-principles calculations reveal that the known B 19 phase is dynamically unstable, and an orthorhombic structure (Pbcm) and a face-centered-cubic B 32 structure ( F d ¯ 3 m ) become stable above ∼4 and 29 GPa, respectively. The predicted, highest-pressure, B 32 phase is composed of two interpenetrating diamond structures, with a structural topology that is quite distinct from that of the other phases of NiTi. Interestingly, the B 32 phase shows an unusual semiconducting characteristic as a result of its unique band structure and the nature of 3 d orbitals localization, whose expected synthesis pressure is accessible to current experimental techniques.

Item Type:	Article
Uncontrolled Keywords:	2018AREP, IA74
Subjects:	03 - Mineral Sciences
Divisions:	03 - Mineral Sciences
Journal or Publication Title:	Physical Review B
Volume:	97
Identification Number:	https://doi.org/10.1103/PhysRevB.97.140104
Depositing User:	Sarah Humbert
Date Deposited:	04 May 2018 10:28
Last Modified:	04 May 2018 10:28
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4261

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