We examine the charge density wave (CDW) properties of 1T-VSe2 crystals grown by chemical vapour transport (CVT) under varying conditions. Specifically, we find that by lowering the growth temperature (Tg< 630∘C), there is a significant increase in both the CDW transition temperature and the residual resistance ratio (RRR) obtained from electrical transport measurements. Using x-ray photoelectron spectroscopy (XPS), we correlate the observed CDW properties with stoichiometry and the nature of defects. In addition, we have optimized a method to grow ultra-high purity 1T-VSe2 crystals with a CDW transition temperature, TCDW = (112.7 ± 0.8) K and maximum residual resistance ratio (RRR) ≈ 49, which is the highest reported thus far. This work highlights the sensitivity of the CDW in 1T-VSe2 to defects and overall stoichiometry, and the importance of controlling the crystal growth conditions of strongly-correlated transition metal dichalcogenides.
@article{arxiv.2001.08020,
title = {Correlation between crystal purity and the charge density wave in 1$T$-VSe$_2$},
author = {C. J. Sayers and L. S. Farrar and S. J. Bending and M. Cattelan and A. J. H. Jones and N. A. Fox and G. Kociok-Köhn and K. Koshmak and J. Laverock and L. Pasquali and E. Da Como},
journal= {arXiv preprint arXiv:2001.08020},
year = {2023}
}