Optical Gyrotropy and the Nonlocal Hall Effect in Chiral Charge Ordered TiSe$_2$

TL;DR

This paper demonstrates that optical gyrotropy and the nonlocal Hall effect can be used to detect broken inversion symmetry in chiral charge ordered TiSe$_2$, providing insights relevant to high-temperature superconductor pseudogap phases.

Contribution

It shows that optical gyrotropy and the nonlocal Hall effect serve as sensitive probes of inversion symmetry breaking in chiral charge ordered TiSe$_2$, a novel application of these phenomena.

Findings

Optical gyrotropy and the nonlocal Hall effect are observed in TiSe$_2$ with chiral charge order.

Estimated gyrotropic constant and optical rotary power suggest measurable effects.

TiSe$_2$ can serve as a model for interpreting Kerr effect measurements in cuprates.

Abstract

It has been suggested that materials which break spatial inversion symmetry, but not time reversal symmetry, will be optically gyrotropic and display a nonlocal Hall effect. The associated optical rotary power and the suggested possibility of inducing a Kerr effect in such materials, in turn are central to recent discussions about the nature of the pseudogap phases of various cuprate high-temperature superconductors. In this letter, we show that optical gyrotropy and the nonlocal Hall effect provide a sensitive probe of broken inversion symmetry in $1T$-TiSe$_2$. This material was recently found to possess a chiral charge ordered phase at low temperatures, in which inversion symmetry is spontaneously broken, while time reversal symmetry remains unbroken throughout its phase diagram. We estimate the magnitude of the resulting gyrotropic constant and optical rotary power and suggest that $1T$-TiSe$_2$ may be employed as a model material in the interpretation of recent Kerr effect measurements in cuprate superconductors.