Resonance Raman Scattering of Topological Insulators Bi2Te3 and Bi2−xSbxTe3−ySey Thin Films | Sciact - CRIS-system of Boreskov Institute of Catalysis

Resonance Raman Scattering of Topological Insulators Bi2Te3 and Bi2−xSbxTe3−ySey Thin Films Full article

Journal

Journal of Raman Spectroscopy
ISSN: 0377-0486 , E-ISSN: 1097-4555

Output data

Year: 2024, DOI: 10.1002/jrs.6751

Tags

anharmonic coupling | Fröhlich strength | polarization-resolved Raman spectroscopy | Raman resonance | topological insulators

Authors

Kumar N. ^1,2 , Surovtsev N.V. ³ , Ishchenko D.V. ¹ , Yunin P.A. ^4,5 , Milekhin I.A. ^1,6 , Tereshchenko O.E. ^1,7 , Milekhin A.G. ^1,6

Affiliations

1	Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2	Tomsk State University, Tomsk, Russia
3	Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirs, Russia
4	Institute for Physics of Microstructures, Russian Academy of Sciences, Afonino, Nizhny Novgorod, Russia
5	Faculty of Radiophysics, Lobachevsky State University, Nizhny Novgorod, Russia
6	Novosibirsk State University, Novosibirsk, Russia
7	Synchrotron Radiation Facility SKIF, Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Koltsovo, Russia

Funding (3)

1	Russian Science Foundation	22-12-20024 (122063000001-1)
2	Ministry of Science and Higher Education of the Russian Federation	FWUR-2024-0042
3	Ministry of Science and Higher Education of the Russian Federation	FSUS-2024-0020

Phonon occupation is temperature (T) dependent; it may participate in scattering with electronic states of topological insulators (TIs). Longitudinal optical (LO) phonons A1 1g and A2 1g in Bi2−xSbxTe3−ySey (BSTS) was resonantly excited by a photon energy (Ep) 2.33 eV due to electronic transition of unoccupied conduction band. The intensity of these modes was enhanced in Bi2Te3 film at Ep 1.87 eV, which is close to the electronic transition of unoccupied Dirac states. Fröhlich coupling strength was the main mechanism for higher intensity of A1 1g and A2 1g modes. At 300 K, the intensity of the A2 1g mode was significantly decayed in both the BSTS and Bi 2Te3 at Ep 2.33 and 1.87 eV due to the anharmonic coupling. However, at similar value of T, spectral profile of A1 1g and E2g modes was not affected because of the lower probability of decay rate of these phonons. In resonant condition, well-resolved Raman forbidden surface modes were observed at T of 50 K. At 300 K, more asymmetric Fano profile of surface phonon was observed due to the anharmonic coupling. The study indicated that at high T, A1 1g mode and anharmonic coupling may become primary cause for scattering with electronic states of the TIs. However, at low T, primarily, both the LO phonons participated in the scattering.

Kumar N. , Surovtsev N.V. , Ishchenko D.V. , Yunin P.A. , Milekhin I.A. , Tereshchenko O.E. , Milekhin A.G.
Resonance Raman Scattering of Topological Insulators Bi2Te3 and Bi2−xSbxTe3−ySey Thin Films
Journal of Raman Spectroscopy. 2024. DOI: 10.1002/jrs.6751 WOS Scopus OpenAlex

Submitted:	Jul 16, 2024
Published online:	Oct 31, 2024

Web of science:	WOS:001362783900001
Scopus:	2-s2.0-85210079056
OpenAlex:	W4404722914

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