Abstract
Charge density waves (CDWs) in transition metal dichalcogenides are the subject of growing scientific interest due to their rich interplay with exotic phases of matter and their potential technological applications. Here, using density functional theory with advanced meta-generalized gradient approximations (meta-GGAs) and linear response time-dependent density functional theory (TDDFT) with state-of-the-art exchange-correlation kernels, we investigate the electronic, vibrational, and optical properties in 1T-TiSe2 with and without CDW. In both bulk and monolayer TiSe2, the electronic bands and phonon dispersions in either normal or CDW (semiconducting) phase are described well via meta-GGAs, which separate the valence and conduction bands just as HSE06 does but with significantly more computational feasibility. The experimentally observed humps of electron energy loss spectroscopy are successfully reproduced in TDDFT. Our work opens the door to simulating these complexities in CDW compounds from first principles by revealing meta-GGAs as an accurate low-cost alternative to HSE06.
| Original language | English |
|---|---|
| Article number | 207 |
| Journal | npj Computational Materials |
| Volume | 10 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2024 |
Funding
This work was supported by the donors of ACS Petroleum Research Fund under New Directions Grant 65973-ND10. A.R. served as Principal Investigator on ACS PRF 65973-ND10 that provided support for H.T. L.Y. and A.R. acknowledge support from Tulane University’s startup fund, which also supports L.Y. This research includes calculations carried out on HPC resources supported in part by the National Science Foundation through major research instrumentation grant number 1625061 and by the US Army Research Laboratory under contract number W911NF-16-2-0189. This research was supported in part by the high performance computing (HPC) resources and services provided by Information Technology at Tulane University, New Orleans, LA. Part of this research (T.B.) was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.