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arXiv · 1511.07574

Microscopic quantum interference in excitonic condensation of Ta$_2$NiSe$_5$

Koudai Sugimoto·Tatsuya Kaneko·Yukinori Ohta
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Abstract

The microscopic quantum interference associated with excitonic condensation in Ta$_2$NiSe$_5$ is studied in the BCS-type mean-field approximation. We show that in ultrasonic attenuation the coherence peak appears just below the transition temperature $T_{\rm c}$ whereas in NMR spin-lattice relaxation the rate rapidly decreases below $T_{\rm c}$; these observations can offer a crucial experimental test for the validity of the excitonic condensation scenario in Ta$_2$NiSe$_5$. We also show that the excitonic condensation manifests itself in a jump of the heat capacity at $T_{\rm c}$ as well as in softening of the elastic shear constant, in accordance with the second-order phase transition observed in Ta$_2$NiSe$_5$.

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Koudai Sugimoto, Tatsuya Kaneko, Yukinori Ohta. 2016-01-18. Microscopic quantum interference in excitonic condensation of Ta$_2$NiSe$_5$. https://doi.org/10.1103/physrevb.93.041105

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