Phonon and thermal expansion properties in Weyl semimetals MX (M = Nb, Ta; X = P, As): ab initio studies. Issue 21 (13th May 2016)

• Record Type: Journal Article
• Authors: Chang, Dahu; Liu, Yaming; Rao, Fengfei; Wang, Fei; Sun, Qiang; Jia, Yu
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 21(2016)
• Page Start: 14503
• Page End: 14508
• Publication Date: 2016-05-13
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c6cp02018f
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Thermal expansion properties of Weyl semimetals MX are determined mainly by the isovolume heat capacity at low temperatures, whereas bulk modulus at high temperatures. 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.