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arXiv · 1811.00772

Temperature-driven Topological Phase Transition and Intermediate Dirac Semimetal Phase in ZrTe$_5$

B. Xu·L. X. Zhao·P. Marsik·E. Sheveleva·F. Lyzwa·Y. M. Dai·G. F. Chen·X. G. Qiu·C. Bernhard
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Abstract

We present an infrared spectroscopy study of ZrTe$_5$, which confirms a recent theoretical proposal that this material exhibits a temperature-driven topological quantum phase transition from a weak to a strong topological insulating state with an intermediate Dirac semimetal state around $T_p \simeq$ 138K. Our study details the temperature evolution of the energy gap in the bulk electronic structure. We found that the energy gap closes around $T_p$ where the optical response exhibits characteristic signatures of a Dirac semimetal state, i.e. a linear frequency-dependent optical conductivity extrapolating to the origin (after subtracting a weak Drude response). This finding allows us to reconcile previous diverging reports about the topological nature of ZrTe$_5$ in terms of a variation of $T_p$ that depends on the crystal growth condition.

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B. Xu, L. X. Zhao, P. Marsik, E. Sheveleva, F. Lyzwa, Y. M. Dai, G. F. Chen, X. G. Qiu, C. Bernhard. 2018-11-02. Temperature-driven Topological Phase Transition and Intermediate Dirac Semimetal Phase in ZrTe$_5$. https://doi.org/10.1103/physrevlett.121.187401

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