Strain effects on phase transitions in transition metal dichalcogenides

Seoung Hun Kang, Young Kyun Kwon

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Abstract

We perform density functional theory calculation to investigate the structural and electronic properties of various two-dimensional transition metal dichalcogenides, MX 2 (M=Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, or W, and X=S or Se), and their strain-induced phase transitions. We evaluate the relative stability and the activation barrier between the octahedral-T and the trigonal-H phases of each MX 2 . It is found that the equilibrium and phase transition characteristics of MX 2 can be classified by the group to which its metal element M belongs in the periodic table. MX 2 with M in the group 4 (Ti, Zr, or Hf), forms an octahedral-T phase, while that with an M in the group 6 (Cr, Mo, or W) does a trigonal-H phase. On the other hand, MX 2 with M in the group 5 (V, Nb, or Ta), which is in-between the groups 4 and 6, may form either phase with a similar stability. It is also found that their electronic structures are strongly correlated to the structural configurations: mostly metallic in the T phase, while semiconducting in the H phase, although there are some exceptions. We also explore the effects of an applied stress and find for some MX 2 materials that the resultant strain, either tensile or compressive, may induce a structural phase transition by reducing the transition energy barrier, which is, in some cases, accompanied by its metal-insulator transition.

Original languageEnglish
Pages (from-to)690-696
Number of pages7
JournalCurrent Applied Physics
Volume19
Issue number6
DOIs
StatePublished - Jun 2019
Externally publishedYes

Funding

We acknowledge financial support from the Korean government through National Research Foundation (NRF) (2015R1A2A2A01006204, 2019R1A2C1005417) and the Korea Evaluation Institute of Industrial Technology (KEIT) (10080625). Some portion of our computational work was done using the resources of the KISTI Supercomputing Center (KSC-2018-C2-0033, KSC-2018-CHA-005) and of the KIAS Center for Advanced Computation Linux Cluster System.

FundersFunder number
Korea Evaluation Institute of Industrial Technology10080625, 2019R1A2C1005417
Korea Institute of Science and Technology InformationKSC-2018-CHA-005, KSC-2018-C2-0033
National Research Foundation of Korea2015R1A2A2A01006204

    Keywords

    • Density functional theory
    • Phase transition
    • Strain effect
    • Transition metal dichalcogenides

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