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arXiv · 1705.05708

Manipulation of type-I and type-II Dirac points in PdTe2 superconductor by external pressure

R. C. Xiao·P. L. Gong·Q. S. Wu·W. J. Lu·M. J. Wei·J. Y. Li·H. Y. Lv·X. Luo·P. Tong·X. B. Zhu·Y. P. Sun
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Abstract

A pair of type-II Dirac cones in PdTe$_2$ was recently predicted by theories and confirmed in experiments, making PdTe$_2$ the first material that processes both superconductivity and type-II Dirac fermions. In this work, we study the evolution of Dirac cones in PdTe$_2$ under hydrostatic pressure by the first-principles calculations. Our results show that the pair of type-II Dirac points disappears at 6.1 GPa. Interestingly, a new pair of type-I Dirac points from the same two bands emerges at 4.7 GPa. Due to the distinctive band structures compared with those of PtSe$_2$ and PtTe$_2$, the two types of Dirac points can coexist in PdTe$_2$ under proper pressure (4.7-6.1 GPa). The emergence of type-I Dirac cones and the disappearance of type-II Dirac ones are attributed to the increase/decrease of the energy of the states at $\Gamma$ and $A$ point, which have the anti-bonding/bonding characters of interlayer Te-Te atoms. On the other hand, we find that the superconductivity of PdTe$_2$ slightly decreases with pressure. The pressure-induced different types of Dirac cones combined with superconductivity may open a promising way to investigate the complex interactions between Dirac fermions and superconducting quasi-particles.

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R. C. Xiao, P. L. Gong, Q. S. Wu, W. J. Lu, M. J. Wei, J. Y. Li, H. Y. Lv, X. Luo, P. Tong, X. B. Zhu, Y. P. Sun. 2017-05-16. Manipulation of type-I and type-II Dirac points in PdTe2 superconductor by external pressure. https://doi.org/10.1103/physrevb.96.075101

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