Analysis of the Scanning Tunneling Microscopy Images of the Charge Density Wave Phase in Quasi-one-dimensional Rb0.3MoO3

TL;DR

This study combines first-principles DFT calculations with STM experiments to analyze the charge density wave phase in Rb0.3MoO3, revealing surface atomic contributions and inhomogeneities affecting CDW periodicity.

Contribution

It provides a detailed explanation of STM images for RbMoO3's CDW phase, highlighting the role of surface Rb atoms and surface states in CDW modulation.

Findings

STM images explained by DFT calculations

Surface Rb atoms influence CDW periodicity

Inhomogeneities in surface wavevector observed and explained

Abstract

The experimental STM images for the CDW phase of the blue bronze RbMoO3 have been successfully explained on the basis of first-principles DFT calculations. Although the density of states near the Fermi level strongly concentrates in two of the three types of Mo atoms Mo-II and Mo-III, the STM measurement mostly probes the contribution of the uppermost O atoms of the surface, associated with the Mo-IO6 octahedra. In addition, it is found that the surface concentration of Rb atoms plays a key role in determining the surface nesting vector and hence the periodicity of the CDW modulation. Significant experimental inhomogeneities of the b* surface component of the wavevector of the modulation, probed by STM, are reported. The calculated changes in the surface nesting vector are consistent with the observed experimental inhomogeneities.