Temperature-driven phase transition of Ti2CN from first-principles calculations

Jin Zhang; Huafeng Dong; Xinfeng Li; Zhenhai Wang; Dong Xiao

doi:10.1039/d2cp01466a

Temperature-driven phase transition of Ti₂CN from first-principles calculations

Phys Chem Chem Phys. 2022 Sep 14;24(35):20848-20855. doi: 10.1039/d2cp01466a.

Authors

Jin Zhang¹, Huafeng Dong², Xinfeng Li³, Zhenhai Wang⁴, Dong Xiao⁵

Affiliations

¹ College of Education for the Future, Beijing Normal University, Zhuhai 519087, China. zhangjin225@bnu.edu.cn.
² School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China.
³ Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, China.
⁴ College of Telecommunications & Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210003, China.
⁵ Key Laboratory of Weak-Light Nonlinear Photonics and School of Physics, Nankai University, Tianjin 300071, China. xiao.dong@nankai.edu.cn.

PMID: 36040355
DOI: 10.1039/d2cp01466a

Abstract

First-principles evolutionary simulations are used to predict the stable compound of Ti₂CN. Body-centered tetragonal I4₁/amd-Ti₂CN is found to be more energetically favorable than the other Ti₂CN compounds at 0 K. The phase stability as a function of temperature for all relevant competing Ti₂CN phases is investigated by means of first-principles calculations and quasi-harmonic approximation. Our calculations predict that I4₁/amd-Ti₂CN undergoes a phase transition to P4₂/mmc at 1698 K and then to R3̄m at 1872 K. The different effects from the harmonic, electronic and quasi-harmonic contributions to the Gibbs free energy for I4₁/amd, P4₂/mmc and R3̄m phases are compared and analyzed. It is found that both the electronic and quasi-harmonic contributions to the Gibbs free energies significantly affect the phase transition curve of Ti₂CN. The calculated temperature-dependent lattice parameter is carefully compared with the previous experimental results. We also provide important thermodynamic quantities as the volumetric expansion coefficient and isothermal bulk modulus and discuss their temperature dependence.