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arXiv · 1404.1157

The three-dimensional topological Dirac semimetal Na$_3$Bi: the ground state phase

Xiyue Cheng·Ronghan Li·Xing-Qiu Chen·Dianzhong Li·Yiyi Li
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Abstract

By means of first-principles calculations, we found that the early characterized three-dimensional topological bulk Dirac semimetal of the $P$6$_3$/$mmc$ Na$_3$Bi is dynamically unstable at the ground state due to the presence of the large imaginary phonon frequencies around the $K$ point. Alternatively, our calculations suggest a new ground state phase which crystalizes in the $P$$\overline3$$c$1 structure with a buckled graphite-like Na/Bi sheets, which is both energetically and dynamically more stable. Moreover, the calculations also uncovered that the $P$$\overline3$$c$1 phase at the ground state is also a topological 3D Dirac semimetal, being exactly the same as the electronic states of the metastable $P$6$_3$/$mmc$ phase.

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Xiyue Cheng, Ronghan Li, Xing-Qiu Chen, Dianzhong Li, Yiyi Li. 2014-04-04. The three-dimensional topological Dirac semimetal Na$_3$Bi: the ground state phase. https://arxiv.org/abs/1404.1157

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