Chiral-Nematic Lattice Instability in Charge Density Wave of 1T-TiSe₂.
- 1Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Republic of Korea.
- 2Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
Abstract
Chiral charge-density waves (CDWs) are a rare form of electronic order with handedness, enabling novel couplings among light, lattice, and topology in quantum materials. Yet the microscopic origin of chirality has remained elusive, even in the prototypical chiral CDW system 1T-TiSe₂. Using ab initio calculations, we investigate the structural stability and electronic structure of competing CDW models in 1T-TiSe₂. We show that a chiral monoclinic ( C2 ) structure is stabilized by the cooperative condensation of multiple phonon modes and reproduces the chiral topography and energy gap observed experimentally. We further find an exceptionally soft potential landscape around this energy-minimized structure, along the direction that removes the remaining rotational symmetry, allowing the lattice to fluctuate through fully asymmetric configurations while its average structure remains chiral. This dynamical chiral CDW naturally reconciles the chiral domains seen by time-averaged topographic probes with the complete loss of symmetry detected by bulk spectroscopy, and clarifies how chiral CDWs emerge from the interplay of lattice instability and fluctuation.
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BibTeX
@article{alghifari2026chiralnematic,
title = {{Chiral-Nematic Lattice Instability in Charge Density Wave of 1T-TiSe₂.}},
author = {Abdurrafi Ahsan Alghifari and Euihwan Do and Jae Whan Park and Han Woong Yeom},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
year = {2026},
month = oct,
doi = {10.1002/advs.78243},
url = {https://europepmc.org/article/MED/42902534},
note = {CC BY},
}
RIS
TY - JOUR
TI - Chiral-Nematic Lattice Instability in Charge Density Wave of 1T-TiSe₂.
AU - Abdurrafi Ahsan Alghifari
AU - Euihwan Do
AU - Jae Whan Park
AU - Han Woong Yeom
PY - 2026
DA - 2026/10/20
JO - Advanced science (Weinheim, Baden-Wurttemberg, Germany)
DO - 10.1002/advs.78243
UR - https://europepmc.org/article/MED/42902534
AB - Chiral charge-density waves (CDWs) are a rare form of electronic order with handedness, enabling novel couplings among light, lattice, and topology in quantum materials. Yet the microscopic origin of chirality has remained elusive, even in the prototypical chiral CDW system 1T-TiSe₂. Using ab initio calculations, we investigate the structural stability and electronic structure of competing CDW models in 1T-TiSe₂. We show that a chiral monoclinic ( C2 ) structure is stabilized by the cooperative condensation of multiple phonon modes and reproduces the chiral topography and energy gap observed experimentally. We further find an exceptionally soft potential landscape around this energy-minimized structure, along the direction that removes the remaining rotational symmetry, allowing the lattice to fluctuate through fully asymmetric configurations while its average structure remains chiral. This dynamical chiral CDW naturally reconciles the chiral domains seen by time-averaged topographic probes with the complete loss of symmetry detected by bulk spectroscopy, and clarifies how chiral CDWs emerge from the interplay of lattice instability and fluctuation.
SN - 2198-3844
ER -