Ferroaxial and nematic transitions in the charge density wave phase of 1T-TiSe$_2$

Fuente: arXiv
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Main Authors: Edwards, Sarah, Rosenberg, Elliott, Maccari, Ilaria, Wen, Jiaqin, Hu, Chaowei, Xu, Xiaodong, Kim, Jong-Woo, Ryan, Philip J., Fernandes, Rafael M., de Juan, Fernando, Gastiasoro, Maria N., Chu, Jiun-Haw
Format: Preprint
Published: 2026
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author Edwards, Sarah
Rosenberg, Elliott
Maccari, Ilaria
Wen, Jiaqin
Hu, Chaowei
Xu, Xiaodong
Kim, Jong-Woo
Ryan, Philip J.
Fernandes, Rafael M.
de Juan, Fernando
Gastiasoro, Maria N.
Chu, Jiun-Haw
author_facet Edwards, Sarah
Rosenberg, Elliott
Maccari, Ilaria
Wen, Jiaqin
Hu, Chaowei
Xu, Xiaodong
Kim, Jong-Woo
Ryan, Philip J.
Fernandes, Rafael M.
de Juan, Fernando
Gastiasoro, Maria N.
Chu, Jiun-Haw
contents Charge density waves (CDWs) with multi-component order parameters can break unexpected symmetries through the interplay of nearly degenerate instabilities. In the widely investigated material 1T-TiSe$_2$, a central question is whether the observed CDW has a chiral character, which would manifest as the spontaneous breaking of mirror and inversion symmetries. Previous experiments have reported conflicting results about the broken symmetries in the CDW phase of 1T-TiSe$_2$. Here, we resolve this controversy by identifying the bulk broken symmetry as ferroaxial, corresponding to the breaking of vertical mirrors while preserving inversion symmetry. Using symmetry-resolved elastoresistivity, we detect the spontaneous emergence of intrinsic off-diagonal elastoresistivity coefficients that satisfy an antisymmetric relation ($m_{xx-yy,xy} \approx -m_{xy,xx-yy}$), providing an unambiguous bulk transport signature of a macroscopic electric toroidal moment. Simultaneous elastocaloric measurements reveal that the onset of ferroaxial order occurs just below the CDW transition. As the temperature is lowered further, a diverging nematic susceptibility signals a distinct rotational symmetry-breaking instability inside the ferroaxial CDW state. Our findings demonstrate that the proposed ``chiral'' CDW in 1T-TiSe$_2$ is actually a centrosymmetric ferroaxial state, reconciling previous surface-sensitive observations with bulk symmetry constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14614
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ferroaxial and nematic transitions in the charge density wave phase of 1T-TiSe$_2$
Edwards, Sarah
Rosenberg, Elliott
Maccari, Ilaria
Wen, Jiaqin
Hu, Chaowei
Xu, Xiaodong
Kim, Jong-Woo
Ryan, Philip J.
Fernandes, Rafael M.
de Juan, Fernando
Gastiasoro, Maria N.
Chu, Jiun-Haw
Strongly Correlated Electrons
Superconductivity
Charge density waves (CDWs) with multi-component order parameters can break unexpected symmetries through the interplay of nearly degenerate instabilities. In the widely investigated material 1T-TiSe$_2$, a central question is whether the observed CDW has a chiral character, which would manifest as the spontaneous breaking of mirror and inversion symmetries. Previous experiments have reported conflicting results about the broken symmetries in the CDW phase of 1T-TiSe$_2$. Here, we resolve this controversy by identifying the bulk broken symmetry as ferroaxial, corresponding to the breaking of vertical mirrors while preserving inversion symmetry. Using symmetry-resolved elastoresistivity, we detect the spontaneous emergence of intrinsic off-diagonal elastoresistivity coefficients that satisfy an antisymmetric relation ($m_{xx-yy,xy} \approx -m_{xy,xx-yy}$), providing an unambiguous bulk transport signature of a macroscopic electric toroidal moment. Simultaneous elastocaloric measurements reveal that the onset of ferroaxial order occurs just below the CDW transition. As the temperature is lowered further, a diverging nematic susceptibility signals a distinct rotational symmetry-breaking instability inside the ferroaxial CDW state. Our findings demonstrate that the proposed ``chiral'' CDW in 1T-TiSe$_2$ is actually a centrosymmetric ferroaxial state, reconciling previous surface-sensitive observations with bulk symmetry constraints.
title Ferroaxial and nematic transitions in the charge density wave phase of 1T-TiSe$_2$
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2603.14614