Structural, mechanical, dynamical and electronic properties and high-pressure behavior of Mo2GeC: A first-principles study

Ab initio predictions of structure and physical properties of the Zr2GaC and Hf2GaC MAX phases under pressure

“…A similar trend can be seen for Young’s and shear modulus of Zr 2 GaC. On the other hand, the Hf 2 GaC MAX phase shows a linear trend, consistent with the other MAX phase studies under pressure 55 , 83 . The mechanical stability of M 2 GaC MAX phases are predicted from the Born stability criteria 84 i.e., C 11 > 0, C 11 − C 12 > 0, C 44 > 0, C 66 > 0, (C 11 + C 12 ) C 33 − 2 > 0.…”

“…The DOS at Fermi level is used to investigate the metallicity at ambient temperature using following expression 55 , 56 : where is the thermally excited number of electrons and is the total number of valence electrons in the unit cell. and are the Boltzmann constant, and value of DOS at Fermi level in unit states/eV/unit cell, respectively.…”

Pressure Dependence of Mechanical and Thermodynamic Properties of MAX‐Phase M2GaC (M = Nb and Ta) from First‐Principles Calculations

“…[ 16 ] The exchange‐correlation energy is represented by the generalized gradient approximation (GGA) in the Perdew–Burke–Eruzerh (PBE) scheme. [ 17 ] The valence electrons involved in the calculation are Nb 4 d 4 5 s 1 , Ta 4 f 14 5 d 3 6 s 2 , Ga 3 d 10 4 s 2 4 p 1 , C 2 s 2 2 p 2 . The Broyden–Fletcher–Goldfarb–Shannon (BFGS) method is used for geometry optimization.…”

“…Khatun et al [ 16 ] studied the effects of temperature (0–1000 K) and pressure (0–50 GPa) on the bulk modulus, Debye temperature, and heat capacity of V 2 AC (A = Al, Ga) and found the heat capacity increases with the increase in temperature. Huang et al [ 17 ] studied the effect of pressure on Mo 2 GeC and found that Mo 2 GeC is dynamically stable between 0 and 50 GPa, and Mo 2 GeC has metallicity, which increases with pressure increase.…”

“…Khatun et al [16] studied the effects of temperature (0-1000 K) and pressure (0-50 GPa) on the bulk modulus, Debye temperature, and heat capacity of V 2 AC (A = Al, Ga) and found the heat capacity increases with the increase in temperature. Huang et al [17] studied the effect of pressure on Mo 2 GeC and found that Mo 2 GeC is dynamically stable between 0 and 50 GPa, and Mo 2 GeC has metallicity, which increases with pressure increase.In fact, almost all previous calculation work mainly focused on the structure and mechanical properties of these ternary carbides at room temperature and pressure. [18,19] To date, there are few reports about the high-pressure behavior of these ternary carbides.…”