Correlation between electronic and structural orders in 1T−TiSe2

Hiroki Ueda,Larissa Boie,Urs Staub,Martin Josef Neugebauer,Max Burian,Federica Fabrizi,Bulat Burganov,Michael Porer,Mahesh Ramakrishnan,Namrata Gurung,Steven Lee Johnson,Sergii Parchenko,José R L Mardegan,Kai Rossnagel

doi:10.1103/physrevresearch.3.l022003

Hiroki Ueda, Larissa Boie + Show 12 more

Open Access

https://doi.org/10.1103/physrevresearch.3.l022003

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Abstract

The correlation between electronic and crystal structures of 1T-TiSe2 in the charge density wave (CDW) state is studied by x-ray diffraction. Three families of reflections are used to probe atomic displacements and the orbital asymmetry in Se. Two distinct onset temperatures are found, TCDW and a lower T* indicative for an onset of Se out-of-plane atomic displacements. T* coincides with a DC resistivity maximum and the onset of the proposed gyrotropic electronic structure. However, no indication for chirality is found. The relation between the atomic displacements and the transport properties is discussed in terms of Ti 3d and Se 4p states that only weakly couple to the CDW order.

Highlights

The correlation between electronic and crystal structures of 1T -TiSe2 in the charge-density wave (CDW) state is studied by x-ray diffraction in order to clarify basic properties in the CDW state, transport properties, and chirality
Detailed investigations of a space-group forbidden reflection in resonant x-ray diffraction (XRD) combined with ab initio simulation are well described by a nonchiral symmetry of electronic and crystal structures in the CDW state
The intensity depends on the azimuthal angle, and the profile is nicely described by ab initio calculations performed by the FDMNES code using a model based on the crystal structure in the CDW state [32] [see Fig. 3(b)]

Summary

Introduction

The correlation between electronic and crystal structures of 1T -TiSe2 in the charge-density wave (CDW) state is studied by x-ray diffraction in order to clarify basic properties in the CDW state, transport properties, and chirality. Besides the anomalous resistivity peak, the CDW state features a circular photogalvanic current, measured with midinfrared circularly polarized light irradiation, interpreted as the occurrence of gyrotropic electronic order [5] and the emergence of chirality [18], both of which have distinct onset temperatures below TCDW.

Results

Conclusion