Chiral Phase Transition in Charge Ordered $1T\mathrm{\text{\ensuremath{-}}}{\mathrm{TiSe}}_{2}$

Chiral Phase Transition in Charge Ordered $1 T − {TiSe}_{2}$

John-Paul Castellan, Stephan Rosenkranz, Ray Osborn, Qing’an Li, K. E. Gray, X. Luo, U. Welp, Goran Karapetrov, J. P. C. Ruff, and Jasper van Wezel

Phys. Rev. Lett. 110, 196404 – Published 7 May 2013

Abstract

It was recently discovered that the low-temperature, charge-ordered phase of $1 T − {TiSe}_{2}$ has a chiral character. This unexpected chirality in a system described by a scalar order parameter could be explained in a model where the emergence of relative phase shifts between three charge density wave components breaks the inversion symmetry of the lattice. Here, we present experimental evidence for the sequence of phase transitions predicted by that theory, going from disorder to nonchiral and finally to chiral charge order. Employing x-ray diffraction, specific heat, and electrical transport measurements, we find that a novel phase transition occurs $\sim 7 K$ below the main charge ordering transition in ${TiSe}_{2}$ , in agreement with the predicted hierarchy of charge-ordered phases.

Received 5 April 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.196404

Authors & Affiliations

John-Paul Castellan¹, Stephan Rosenkranz¹, Ray Osborn¹, Qing’an Li¹, K. E. Gray¹, X. Luo¹, U. Welp¹, Goran Karapetrov^1,2, J. P. C. Ruff^3,4, and Jasper van Wezel^1,5,*

¹Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
²Physics Department, Drexel University, Philadelphia, Pennsylvania 19104, USA
³Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
⁴CHESS, Cornell University, Ithaca, New York 14853, USA
⁵H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL United Kingdom