Pressure induced topological and structural phase transitions in 1T-TiSe2: a Raman study. (22nd February 2019)

• Record Type: Journal Article
• Authors: Rajaji, V; Janaky, S; Sarma, Saurav Ch.; Peter, Sebastian C; Narayana, Chandrabhas
• Is Part Of: Journal of physics. Volume 31:Number 16(2019)
• Publication Date: 2019-02-22
• Subjects: Raman spectroscopy -- high pressure -- topological phase transition -- structural phase transition -- transition metal dichalcogenide; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ab01bb
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: High pressure Raman spectroscopy studies on 1T-TiSe2 were carried out up to ~20.5 GPa. Based on the anomalies in phonon linewidth (lifetime) and phonon frequency of A 1g mode, we observe three transitions at ~2.5 GPa, ~6.0 GPa and ~15 GPa. The transitions at ~2.5 and ~6.0 GPa are the two topological phase transitions consistent with the theoretical prediction by Zhu et al in 1T-TiSe2 under pressure, namely, a topological trivial to non-trivial transition ( Z 2 = 1) and topological non-trivial to trivial transition ( Z 2 = 0). The trigonal (1T) phase of TiSe2 is stable up to ~15 GPa beyond which it undergoes structural transition as seen from the appearance of new Raman modes. There is a coexistence of the 1T and the new high-pressure phase up to ~19 GPa. The structural transition is completely reversible as seen from the appearance of 1T phase Raman spectra upon release of the pressure.