title: Phonon and thermal expansion properties in Weyl semimetals MX (M = Nb, Ta; X = P, As): ab initio studies.
abstract: Weyl semimetal (WSM) is a new type of topological quantum material for future spintronic devices. Using the first-principles density functional theory, we systematically investigated the thermal expansion properties, and the temperature dependence of isovolume heat capacity and bulk modulus in WSMs MX (M = Nb, Ta; X = P, As). We also presented the phonon dispersion curves and its variation under stress in MX and the anisotropic thermal expansion properties due to the anisotropic crystal structure in WSMs have been predicted in our calculations. Intriguing, we found that the heat capacities increase more rapidly with increasing temperature in the low temperature region for all MX. Furthermore, our results showed that the thermal expansion properties are determined mainly by the isovolume heat capacity at low temperatures, while the bulk modulus has the major effect at high temperatures. These results are useful for applications of WSMs in electronic and spintronic devices.
authors.affiliation: International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China. wfei@zzu.edu.cn jiayu@zzu.edu.cn.
authors.forename: Dahu
authors.initials: D
authors.lastname: Chang
authors.forename: Yaming
authors.initials: Y
authors.lastname: Liu
authors.forename: Fengfei
authors.initials: F
authors.lastname: Rao
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Yu
authors.initials: Y
authors.lastname: Jia