Charge Density Waves in Exfoliated Films of van der Waals Materials: Evolution of Raman Spectrum in TiSe2

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• 作者：Pradyumna Goli ; Javed Khan ; Darshana Wickramaratne ; Roger K. Lake ; Alexander A. Balandin
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：November 14, 2012
• 年：2012
• 卷：12
• 期：11
• 页码：5941-5945
• 全文大小：369K
• 年卷期：v.12,no.11(November 14, 2012)
• ISSN：1530-6992

文摘

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 TiSe₂ 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 TiSe₂ 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.

Keywords:

Charge density waves; van der Waals materials; titanium diselenide; Raman spectrum modification