Charge density waves in exfoliated films of van der Waals materials: evolution of Raman spectrum in TiSe2

Nano Lett. 2012 Nov 14;12(11):5941-5. doi: 10.1021/nl303365x. Epub 2012 Oct 25.

Abstract

A number of the charge-density-wave materials reveal a transition to the macroscopic quantum state around 200 K. We used graphene-like mechanical exfoliation of TiSe(2) crystals to prepare a set of films with different thicknesses. The transition temperature to the charge-density-wave state was determined via modification of Raman spectra of TiSe(2) films. It was established that the transition temperature can increase from its bulk value to ~240 K as the thickness of the van der Waals films reduces to the nanometer range. The obtained results are important for the proposed applications of such materials in the collective-state information processing, which require room-temperature operation.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.