Rajaji, V. ; Arora, Raagya ; Sarma, Saurav Ch. ; Joseph, B. ; Peter, Sebastian C. ; Waghmare, Umesh V. ; Narayana, Chandrabhas (2019) Phonon signatures of multiple topological quantum phase transitions in compressed TlBiS2 : A combined experimental and theoretical study Physical Review B: Condensed Matter and Materials Physics, 99 (18). ISSN 2469-9950
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Official URL: http://doi.org/10.1103/PhysRevB.99.184109
Related URL: http://dx.doi.org/10.1103/PhysRevB.99.184109
Abstract
We report the hydrostatic pressure induced two topological phase transitions in strong spin-orbit coupled material TlBiS 2 at room temperature. Frequencies of the A 1g and E g phonons are observed to increase monotonically up to ∼4.0 GPa, but with a clear slope change in A 1g mode at ∼1.8 GPa. Interestingly, there are two clear anomalies noticed in phonon linewidths of E g mode at pressures ∼0.5 and ∼1.8 GPa. Such anomalies are evidence of isostructural electronic transitions associated with unusual electron-phonon coupling. The high-pressure synchrotron powder diffraction and Raman show a first-order phase transition above 4 GPa. First-principles density functional theory-based calculations of electronic band structure, topological invariant Z 2 and mirror Chern number n M reveal that the phonon anomalies at ∼0.5 and ∼1.8 GPa are linked to the band inversions at and F points of the Brillouin zone respectively. The first band inversion at point at ∼0.5 GPa changes the Z 2 from 0 to 1 leading to the transition of TlBiS 2 system into a topological insulator. The second band inversion at F point at ∼1.8 GPa results in n M = 2, revealing a transition to a topological crystalline insulating state. Therefore the applied pressure systematically tunes the electronic states of TlBiS 2 from a normal semiconductor to a topological insulator and finally into a topological crystalline insulator at two distinct pressures of ∼0.5 and ∼1.8 GPa respectively, before undergoing a structural phase transition at ∼4 GPa.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Physical Society. |
ID Code: | 124175 |
Deposited On: | 08 Nov 2021 06:33 |
Last Modified: | 08 Nov 2021 06:33 |
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