Publication

Helical fluctuations in the Raman response of the topological insulator Bi2Se3

Helmuth Berger
2011
Journal Articles

Abstract

The topological insulator Bi2Se3 shows a Raman-scattering (RS) response related to topologically protected surface states amplified by a resonant interband transition. Most significantly this signal has a characteristic Lorentzian lineshape and spin-helical symmetry due to collision-dominated scattering of Dirac states at the Fermi level E-F on bulk-valence states. Its resonance energy, temperature, and doping dependence points to a high selectivity of this process. Its scattering rate (Gamma approximate to 40 cm(-1) approximate to 5 meV) is comparable to earlier observations, e. g., in spin-polaron systems. Although the observation of topological surface states in RS is limited to resonance conditions, this study represents a quite clean case which is not polluted by symmetry forbidden contributions from the bulk.

Official source

https://infoscience.epfl.ch/entities/publication/ba3d8f0a-13ff-448f-b2cf-8af26290cc60

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Helmuth Berger
2011
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/ba3d8f0a-13ff-448f-b2cf-8af26290cc60

About this result

Related concepts (32)

Raman scattering

Raman scattering or the Raman effect (ˈrɑːmən) is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower energy. This is called normal Stokes Raman scattering. The effect is exploited by chemists and physicists to gain information about materials for a variety of purposes by performing various forms of Raman spectroscopy.

Topological insulator

A topological insulator is a material whose interior behaves as an electrical insulator while its surface behaves as an electrical conductor, meaning that electrons can only move along the surface of the material. A topological insulator is an insulator for the same reason a "trivial" (ordinary) insulator is: there exists an energy gap between the valence and conduction bands of the material. But in a topological insulator, these bands are, in an informal sense, "twisted", relative to a trivial insulator.

Raman spectroscopy

Raman spectroscopy (ˈrɑːmən) (named after Indian physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified. Raman spectroscopy relies upon inelastic scattering of photons, known as Raman scattering.

Related publications (32)

Helical fluctuations in the Raman response of the topological insulator Bi2Se3

Chat with Graph Search

Weyl metallic state induced by helical magnetic order

Thermoelectric power of overdoped Tl2201 crystals: charge density waves and T1 and T2 resistivities

Impact of microwave beam scattering by density fluctuations on the electron-cyclotron power deposition profile in tokamaks