Scanning tunneling microscopy study of the CeTe3 charge density wave

TL;DR

This study uses scanning tunneling microscopy to analyze the surface charge distribution and charge density wave in CeTe3, revealing atomic lattice details and subsurface contributions at 77 K.

Contribution

It provides the first detailed STM characterization of CeTe3's surface charge distribution and identifies subsurface lattice effects supported by electronic structure calculations.

Findings

Observation of Te atomic lattice and CDW modulations at 77 K

Identification of subsurface Ce lattice contributions

Fourier analysis revealing wave vector mixing effects

Abstract

We have studied the nature of the surface charge distribution in CeTe3. This is a simple, cleavable, layered material with a robust one-dimensional incommensurate charge density wave (CDW). Scanning tunneling microscopy (STM) has been applied on the exposed surface of a cleaved single crystal. At 77 K, the STM images show both the atomic lattice of surface Te atoms arranged in a square net and the CDW modulations oriented at 45 degrees with respect to the Te net. Fourier transform of the STM data shows Te square lattice peaks, and peaks related to the CDW oriented at 45 degrees to the lattice peaks. In addition, clear peaks are present, consistent with subsurface structure and wave vector mixing effects. These data are supported by electronic structure calculations, which show that the subsurface signal most likely arises from a lattice of Ce atoms situated 2.53 angstroms below the surface Te net.