Zha Xian-Hu, Ma Xiufang, Du Shiyu, Zhang Rui-Qin, Tao Ran, Luo Jing-Ting, Fu Chen
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.
Engineering Laboratory of Advanced Energy Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China.
Inorg Chem. 2022 Jan 31;61(4):2129-2140. doi: 10.1021/acs.inorgchem.1c03358. Epub 2021 Dec 22.
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 TiAC (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 TiAC, 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. TiSC presents the largest Young's modulus of 360 GPa, which is 6.82% higher than that in the well-studied TiSiC. TiSbC is a mechanical quasi-isotropic configuration. After checking the mechanical, dynamical, and thermodynamic stability, TiAC (A = Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Sb, Au, Hg, Pb, TI, and Po) are stable, while TiAC (A = Fe, Co, Zn, Se, Ru, Rh, Pd, Ag, Te, Ir, Pt, and Bi) are metastable. Compared to TiAlC, TiAC (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 TiCT (T denotes surface groups) with a large flake size. All of the configurations are metallic, and TiAC (A = Fe and Co) are magnetic. Based on the phonon dispersion and electronic structure, these TiAC configurations might have potential applications in phononic crystals and topological materials.
兼具金属和陶瓷特性且作为MXenes前驱体的MAX相已引起广泛关注。近年来，A元素取代已被证明是丰富MAX家族的有效方案。为探索更多可能的MAX成员，本文研究了31种TiAC（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、Tl、Pb、Bi和Po）构型的结构、力学和电子性质以及稳定性。此外，还研究了涉及将MAX剥离成MXenes可能性的界面强度。A元素在TiAC的晶格参数和力学强度中起关键作用，Ti和A价轨道之间的d-d和p-d杂化协同效应很好地解释了它们的变化。TiSC的杨氏模量最大，为360 GPa，比研究充分的TiSiC高6.82%。TiSbC是一种力学准各向同性构型。在检查力学、动力学和热力学稳定性后，TiAC（A = Al、Si、P、S、Ga、Ge、As、Cd、In、Sn、Sb、Au、Hg、Pb、Tl和Po）是稳定的，而TiAC（A = Fe、Co、Zn、Se、Ru、Rh、Pd、Ag、Te、Ir、Pt和Bi）是亚稳的。与TiAlC相比，TiAC（A = Ag、Sb、Te、Bi和Po）在Ti-A界面表现出低得多的界面强度以及相邻Ti-C和Ti-A界面的界面强度之间更大的比值。这意味着这些构型是合成大尺寸薄片TiCT（T表示表面基团）的有前景的前驱体。所有构型都是金属性的，且TiAC（A = Fe和Co）是磁性的。基于声子色散和电子结构，这些TiAC构型可能在声子晶体和拓扑材料中有潜在应用。
