Role of the A-Element in the Structural, Mechanical, and Electronic Properties of Ti3AC2 MAX Phases

Xian-Hu Zha; Xiufang Ma; Shiyu Du; Rui-Qin Zhang; Ran Tao; Jing-Ting Luo; Chen Fu

doi:10.1021/acs.inorgchem.1c03358

Role of the A-Element in the Structural, Mechanical, and Electronic Properties of Ti₃AC₂ MAX Phases

Inorg Chem. 2022 Jan 31;61(4):2129-2140. doi: 10.1021/acs.inorgchem.1c03358. Epub 2021 Dec 22.

Authors

Xian-Hu Zha¹, Xiufang Ma¹, Shiyu Du², Rui-Qin Zhang³, Ran Tao¹, Jing-Ting Luo¹, Chen Fu¹

Affiliations

¹ Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
² Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China.
³ Department of Physics, City University of Hong Kong, Kowloon, Hong Kong SAR, China.

PMID: 34935376
DOI: 10.1021/acs.inorgchem.1c03358

Abstract

Combining metallic and ceramic properties, and as precursors for MXenes, MAX phases have attracted extensive attention. In recent years, A-element substitution has been demonstrated as an effective scheme to enrich the MAX family. To explore more possible MAX members, the structural, mechanical, and electronic properties and stabilities of 31 Ti₃AC₂ (A = Al, Si, P, S, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Os, Ir, Pt, Au, Hg, TI, Pb, Bi, and Po) configurations are investigated in this work. Moreover, the interfacial strength implicating the possibility of exfoliating MAX into MXenes is examined. The A-element plays a crucial role in the lattice parameters and mechanical strength of Ti₃AC₂, and their variations are well explained by the synergistic effects of d-d and p-d hybridizations between the valence orbitals of Ti and A. Ti₃SC₂ presents the largest Young's modulus of 360 GPa, which is 6.82% higher than that in the well-studied Ti₃SiC₂. Ti₃SbC₂ is a mechanical quasi-isotropic configuration. After checking the mechanical, dynamical, and thermodynamic stability, Ti₃AC₂ (A = Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Sb, Au, Hg, Pb, TI, and Po) are stable, while Ti₃AC₂ (A = Fe, Co, Zn, Se, Ru, Rh, Pd, Ag, Te, Ir, Pt, and Bi) are metastable. Compared to Ti₃AlC₂, Ti₃AC₂ (A = Ag, Sb, Te, Bi, and Po) exhibit much lower interfacial strength in Ti-A interfaces and larger ratios between the interfacial strengths of neighboring Ti-C and Ti-A interfaces. This implies that these configurations are promising precursors for the synthesis of Ti₃C₂T_x (T_x denotes surface groups) with a large flake size. All of the configurations are metallic, and Ti₃AC₂ (A = Fe and Co) are magnetic. Based on the phonon dispersion and electronic structure, these Ti₃AC₂ configurations might have potential applications in phononic crystals and topological materials.