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Detection of topological phase transitions through entropy measurements: the case of germanene

Detection of topological phase transitions through entropy measurements: the case of germanene
Detection of topological phase transitions through entropy measurements: the case of germanene

We propose a characterization tool for studies of the band structure of new materials promising for the observation of topological phase transitions. We show that a specific resonant feature in the entropy per electron dependence on the chemical potential may be considered as a fingerprint of the transition between topological and trivial insulator phases. The entropy per electron in a honeycomb two-dimensional crystal of germanene subjected to the external electric field is obtained from the first-principles calculation of the density of electronic states and the Maxwell relation. We demonstrate that, in agreement with the recent prediction of the analytical model, strong spikes in the entropy per particle dependence on the chemical potential appear at low temperatures. They are observed at the values of the applied bias both below and above the critical value that corresponds to the transition between the topological insulator and trivial insulator phases, whereas the giant resonant feature in the vicinity of the zero chemical potential is strongly suppressed at the topological transition point, in the low-temperature limit. In a wide energy range, the van Hove singularities in the electronic density of states manifest themselves as zeros in the entropy per particle dependence on the chemical potential.

2469-9950
Grassano, D.
5bfd4e6c-008a-40de-8d09-54fb6c6b1f80
Pulci, O.
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Shubnyi, V.O.
010ea571-da00-4a9b-b3c5-5c02cad23046
Sharapov, S.G.
28178735-49e1-4e3f-92d5-06e1d69e5dd1
Gusynin, V.P.
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Kavokin, A.V.
70ffda66-cfab-4365-b2db-c15e4fa1116b
Varlamov, A.A.
45a0f163-f9c9-425b-af0b-50be123c8564
Grassano, D.
5bfd4e6c-008a-40de-8d09-54fb6c6b1f80
Pulci, O.
3a094841-bc0c-484a-a499-245f82b8f1fe
Shubnyi, V.O.
010ea571-da00-4a9b-b3c5-5c02cad23046
Sharapov, S.G.
28178735-49e1-4e3f-92d5-06e1d69e5dd1
Gusynin, V.P.
5564d9c2-493c-49dc-9c33-77e80bec892f
Kavokin, A.V.
70ffda66-cfab-4365-b2db-c15e4fa1116b
Varlamov, A.A.
45a0f163-f9c9-425b-af0b-50be123c8564

Grassano, D., Pulci, O., Shubnyi, V.O., Sharapov, S.G., Gusynin, V.P., Kavokin, A.V. and Varlamov, A.A. (2018) Detection of topological phase transitions through entropy measurements: the case of germanene. Physical Review B, 97 (20), [205442]. (doi:10.1103/PhysRevB.97.205442).

Record type: Article

Abstract

We propose a characterization tool for studies of the band structure of new materials promising for the observation of topological phase transitions. We show that a specific resonant feature in the entropy per electron dependence on the chemical potential may be considered as a fingerprint of the transition between topological and trivial insulator phases. The entropy per electron in a honeycomb two-dimensional crystal of germanene subjected to the external electric field is obtained from the first-principles calculation of the density of electronic states and the Maxwell relation. We demonstrate that, in agreement with the recent prediction of the analytical model, strong spikes in the entropy per particle dependence on the chemical potential appear at low temperatures. They are observed at the values of the applied bias both below and above the critical value that corresponds to the transition between the topological insulator and trivial insulator phases, whereas the giant resonant feature in the vicinity of the zero chemical potential is strongly suppressed at the topological transition point, in the low-temperature limit. In a wide energy range, the van Hove singularities in the electronic density of states manifest themselves as zeros in the entropy per particle dependence on the chemical potential.

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Detection of topological phase transitions through entropy measurements: The case of germanene - Accepted Manuscript
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Accepted/In Press date: 8 March 2018
e-pub ahead of print date: 25 May 2018
Published date: 25 May 2018
Additional Information: Author Kavokin confirmed Arxiv copy 1802.01348v2 is AM .

Identifiers

Local EPrints ID: 421685
URI: http://eprints.soton.ac.uk/id/eprint/421685
ISSN: 2469-9950
PURE UUID: d922dbd0-dd4d-4956-9cfb-292f06369ae7

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Date deposited: 21 Jun 2018 16:30
Last modified: 25 Nov 2021 18:54

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Contributors

Author: D. Grassano
Author: O. Pulci
Author: V.O. Shubnyi
Author: S.G. Sharapov
Author: V.P. Gusynin
Author: A.V. Kavokin
Author: A.A. Varlamov

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