title: Density functional theory investigation of the phonon instability, thermal equation of state and melting curve of Mo.
abstract: The phonon instability and thermal equation of state of Mo are extensively investigated using density functional theory. The calculated phonon dispersion curves agree well with experiments. Under compression, we captured a large softening in the transverse acoustic (TA) branches of body-centred cubic Mo. When the pressure is raised to 716 GPa, the frequencies along Γ-N in the TA branches soften to imaginary frequencies, indicating structural instability. For face-centred cubic Mo, the phonon calculations predicted the stability by promoting the frequencies from imaginary to real. Within quasi-harmonic approximation, we predicted the thermal equation of state and some other properties including the thermal expansion coefficient α, product αK(T), heat capacity C(V), entropy S, Grüneisen parameter γ and Debye temperature Θ(D). The melting curves of Mo were also obtained successfully.
authors.affiliation: College of Physical Science and Technology, Sichuan University, Chengdu, 610064, China. zhaoyizeng@126.com
authors.forename: Zhao-Yi
authors.initials: ZY
authors.lastname: Zeng
authors.forename: Cui-E
authors.initials: CE
authors.lastname: Hu
authors.forename: Xiang-Rong
authors.initials: XR
authors.lastname: Chen
authors.forename: Xiu-Lu
authors.initials: XL
authors.lastname: Zhang
authors.forename: Ling-Cang
authors.initials: LC
authors.lastname: Cai
authors.forename: Fu-Qian
authors.initials: FQ
authors.lastname: Jing