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Investigation on the Stability, Elastic Properties, and Electronic Structure of Mg 2 Si Doped with Different Concentrations of Cu: A First‐Principles Calculation
Author(s) -
Ma Tianyu,
Liu Tongyu,
Ren Yuyan,
Li Yingmin
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000597
Subject(s) - materials science , intermetallic , dopant , doping , electronic structure , crystallography , electronic band structure , crystal structure , density functional theory , alloy , covalent bond , condensed matter physics , computational chemistry , chemistry , metallurgy , physics , optoelectronics , organic chemistry
Herein, the effects of Cu doping with different concentrations on the stability, elastic properties, and electronic structure of Mg 2 Si are investigated by first‐principles calculations based on density functional theory. The research results show that Mg 2 Si and Mg 8− x Si 4− y Cu x + y ( x , y ) = {(0.125, 0), (0, 0.125), (0.25, 0), (0, 0.25), (0.5, 0), (0, 0.5), (1, 0), (0, 1)} are stable in the system. The Cu atoms tend to preoccupy Mg sites in Mg 2 Si lattices, and the alloying ability is stronger than that of Mg 8 Si 4− y Cu y ( y = 0.125, 0.25, 0.5, 1). Although all dopants are brittle phases, the doping behavior of Cu atoms improves the elastic and plastic properties of the Mg 2 Si alloy system. The bonding modes of the crystal are also changed. The SiCu covalent bond formed by Mg 8− x Si 4 Cu x ( x = 0.125, 0.25, 0.5, 1) further increases the structure stability. Meanwhile, Mg 7 Si 4 Cu and Mg 8 Si 3 Cu are changed from semiconducting to metallic state by energy band structure analysis. It not only increases the carrier concentration, but also reduces the free electron transition energy, which improves the conductivity of the intrinsic Mg 2 Si. These investigations will provide some theoretical basis for the application of Mg 2 Si intermetallic compounds in structural materials and thermoelectric materials.