Surface vibrational modes of the topological insulator Bi2Se3 observed by Raman spectroscopy

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F17%3A39910406" target="_blank" >RIV/00216275:25310/17:39910406 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1103/PhysRevB.95.245406" target="_blank" >http://dx.doi.org/10.1103/PhysRevB.95.245406</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.95.245406" target="_blank" >10.1103/PhysRevB.95.245406</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Surface vibrational modes of the topological insulator Bi2Se3 observed by Raman spectroscopy

Popis výsledku v původním jazyce

We present a polarization resolved Raman scattering study of surface vibration modes in the topological insulator Bi2Se3 single crystal and thick films. Besides the four Raman active bulk phonons, we observed four additional modes with much weaker intensity and slightly lower energy than the bulk counterparts. Using symmetry analysis, we assigned these additional modes to out-of-plane surface phonons. Comparing with first-principle calculations, we conclude that the appearance of these modes is due to c-axis lattice distortion and van der Waals gap expansion near the crystal surface. Two of the surface modes at 60 and 173 cm(-1) are associated with Raman active A(1g) bulk phonon modes, the other two at 136 and 158 cm(-1) are associated with infrared active bulk phonons with A(2u) symmetry. The latter become Raman allowed due to reduction of crystalline symmetry from D-3d in the bulk to C-3v on the crystal surface. In particular, the 158 cm(-1) surface phonon mode shows a Fano line shape under resonant excitation, suggesting interference in the presence of electron-phonon coupling of the surface excitations.

Název v anglickém jazyce

Surface vibrational modes of the topological insulator Bi2Se3 observed by Raman spectroscopy

Popis výsledku anglicky

We present a polarization resolved Raman scattering study of surface vibration modes in the topological insulator Bi2Se3 single crystal and thick films. Besides the four Raman active bulk phonons, we observed four additional modes with much weaker intensity and slightly lower energy than the bulk counterparts. Using symmetry analysis, we assigned these additional modes to out-of-plane surface phonons. Comparing with first-principle calculations, we conclude that the appearance of these modes is due to c-axis lattice distortion and van der Waals gap expansion near the crystal surface. Two of the surface modes at 60 and 173 cm(-1) are associated with Raman active A(1g) bulk phonon modes, the other two at 136 and 158 cm(-1) are associated with infrared active bulk phonons with A(2u) symmetry. The latter become Raman allowed due to reduction of crystalline symmetry from D-3d in the bulk to C-3v on the crystal surface. In particular, the 158 cm(-1) surface phonon mode shows a Fano line shape under resonant excitation, suggesting interference in the presence of electron-phonon coupling of the surface excitations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review B

ISSN

2469-9950

e-ISSN

—

Svazek periodika

95

Číslo periodika v rámci svazku

24

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

9

Strana od-do

"245406-1"-"245406-9"

Kód UT WoS článku

000402973800007

EID výsledku v databázi Scopus

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