Multiple Charge density waves and lattice superstructures in thin-layer TmTe2 and TmTe3

TL;DR

This study reports the growth and analysis of thin-layer thulium tellurides (TmTe2 and TmTe3) on graphene/SiC, revealing charge density waves, lattice superstructures, and semiconducting electronic properties, advancing understanding of their surface phenomena.

Contribution

It demonstrates the growth of ultrathin TmTe2 and TmTe3 layers and characterizes their surface charge density waves and superstructures using STM, highlighting their dual origins and semiconducting nature.

Findings

Observation of two distinct charge density waves in TmTe3.

Identification of various lattice superstructures on TmTe2 and TmTe3 surfaces.

Electronic structures are semiconducting in these thin films.

Abstract

We have grown thulium tellurides (TmTe2, TmTe3) thin layers (less than four layers) on graphene/SiC (0001) by molecular beam epitaxy. The charge density waves (CDWs) and lattice superstructures (LSs) are investigated by scanning tunneling microscopy. Clear CDW patterns in real space are observed on surface of metallic TmTe3. Two CDWs are with wave vectors 0.29c* and 0.31a* respectively. LSs with various periods are unveiled on the surface of TmTe2 and TmTe3. The electronic structures of these films are semiconducting. These results show that superstructures in rare earth tellurides can have two origins, CDWs or LSs.