Faculty Publications

Title

Distinct surface and bulk charge density waves in ultrathin 1T-Ta S2

Document Type

Article

Journal/Book/Conference Title

Physical Review B - Condensed Matter and Materials Physics

Volume

94

Issue

20

Abstract

We employ low-frequency Raman spectroscopy to study the nearly commensurate (NC) to commensurate (C) charge density wave (CDW) transition in 1T-TaS2 ultrathin flakes protected from oxidation. We identify additional modes originating from C-phase CDW phonons that are distinct from those seen in bulk 1T-TaS2. We attribute these to CDW modes from the surface layers. By monitoring individual modes with temperature, we find that surfaces undergo a separate, low-hysteresis NC-C phase transition that is decoupled from the transition in the bulk layers. This indicates the activation of a secondary phase nucleation process in the limit of weak interlayer interaction, which can be understood from energy considerations.

Original Publication Date

1-1-2016

DOI of published version

10.1103/PhysRevB.94.201108

Repository

UNI ScholarWorks, Rod Library, University of Northern Iowa

Language

en

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