Quasidegenerate charge-density wave states in 1T-TiSe$_2$

Fuente: arXiv
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Main Authors: Mun, Seungrok, Choi, Woojin, Im, Hayoon, Mo, Sung-Kwan, Hwang, Choongyu, Hwang, Jinwoong, Kim, Heung-Sik
Format: Preprint
Published: 2025
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author Mun, Seungrok
Choi, Woojin
Im, Hayoon
Mo, Sung-Kwan
Hwang, Choongyu
Hwang, Jinwoong
Kim, Heung-Sik
author_facet Mun, Seungrok
Choi, Woojin
Im, Hayoon
Mo, Sung-Kwan
Hwang, Choongyu
Hwang, Jinwoong
Kim, Heung-Sik
contents Transition metal dichalcogenides have been actively studied for their intriguing charge density wave (CDW) formations and their impacts on material properties. Among these, 1T-TiSe$_2$ is well-known to exhibit a 2$\times$2$\times$2 CDW state transition at 200 K, but its true ground state nature remains under debate. In this study, we investigate possible CDW states in 1T-TiSe$_2$ and their consequences for transport properties by employing first-principles electronic structure calculations and angle-resolved photoemission spectroscopy. We identify seven distinct types of 2$\times$2$\times$2 CDW phases, most of which have not been reported previously. All of these phases are nearly degenerate in energy with each other ($< 1.41$ meV per formula unit). Using the band unfolding technique, we compare the electronic band structures of these CDW phases with experimental angle-resolved photoemission spectroscopy data. Our findings support the presence of a possible second phase transition at 165 K and suggest a new intermediate CDW order between 165 and 200 K that was previously unexplored. This result provides a possible resolution to the conflict between previous reports on the ground state symmetry of 1T-TiSe$_2$, and opens a viable route to phase engineering of 1T-TiSe$_2$ for functional applications.
format Preprint
id arxiv_https___arxiv_org_abs_2509_06414
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quasidegenerate charge-density wave states in 1T-TiSe$_2$
Mun, Seungrok
Choi, Woojin
Im, Hayoon
Mo, Sung-Kwan
Hwang, Choongyu
Hwang, Jinwoong
Kim, Heung-Sik
Materials Science
Transition metal dichalcogenides have been actively studied for their intriguing charge density wave (CDW) formations and their impacts on material properties. Among these, 1T-TiSe$_2$ is well-known to exhibit a 2$\times$2$\times$2 CDW state transition at 200 K, but its true ground state nature remains under debate. In this study, we investigate possible CDW states in 1T-TiSe$_2$ and their consequences for transport properties by employing first-principles electronic structure calculations and angle-resolved photoemission spectroscopy. We identify seven distinct types of 2$\times$2$\times$2 CDW phases, most of which have not been reported previously. All of these phases are nearly degenerate in energy with each other ($< 1.41$ meV per formula unit). Using the band unfolding technique, we compare the electronic band structures of these CDW phases with experimental angle-resolved photoemission spectroscopy data. Our findings support the presence of a possible second phase transition at 165 K and suggest a new intermediate CDW order between 165 and 200 K that was previously unexplored. This result provides a possible resolution to the conflict between previous reports on the ground state symmetry of 1T-TiSe$_2$, and opens a viable route to phase engineering of 1T-TiSe$_2$ for functional applications.
title Quasidegenerate charge-density wave states in 1T-TiSe$_2$
topic Materials Science
url https://arxiv.org/abs/2509.06414