Bera, Achintya and Pal, Koushik and Muthu, DVS and Sen, Somaditya and Guptasarma, Prasenjit and Waghmare, UV and Sood, AK (2013) Sharp raman anomalies and broken adiabaticity at a pressure induced transition from band to topological insulator in Sb2Se3. In: Physical Review Letters, 110 (10). 107401_1-107401_5.
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Abstract
The nontrivial electronic topology of a topological insulator is thus far known to display signatures in a robust metallic state at the surface. Here, we establish vibrational anomalies in Raman spectra of the bulk that signify changes in electronic topology: an E-g(2) phonon softens unusually and its linewidth exhibits an asymmetric peak at the pressure induced electronic topological transition (ETT) in Sb2Se3 crystal. Our first-principles calculations confirm the electronic transition from band to topological insulating state with reversal of parity of electronic bands passing through a metallic state at the ETT, but do not capture the phonon anomalies which involve breakdown of adiabatic approximation due to strongly coupled dynamics of phonons and electrons. Treating this within a four-band model of topological insulators, we elucidate how nonadiabatic renormalization of phonons constitutes readily measurable bulk signatures of an ETT, which will facilitate efforts to develop topological insulators by modifying a band insulator. DOI: 10.1103/PhysRevLett.110.107401
Item Type: | Journal Article |
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Publication: | Physical Review Letters |
Publisher: | American Physical Society |
Additional Information: | Copyright of this article belongs to American Physical Society. |
Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
Date Deposited: | 11 Apr 2013 05:30 |
Last Modified: | 11 Apr 2013 05:30 |
URI: | http://eprints.iisc.ac.in/id/eprint/46308 |
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