The structural, elastic constants and anisotropy of RuB2 under pressure are investigated by first-principles calculations based on the plane wave pseudopotential density functional theory method within the local densi...The structural, elastic constants and anisotropy of RuB2 under pressure are investigated by first-principles calculations based on the plane wave pseudopotential density functional theory method within the local density approximation （LDA） as well as the generalized gradient approximation （GGA） for exchange and correlation. The results accord well with the available experimental and other theoretical data. The elastic constants, elastic anisotropy, and Debye temperature ／varTheta as a function of pressure are presented. It is concluded that RuB2 is brittle in nature at low pressure, whereas it becomes ductile at higher pressures. An analysis for the calculated elastic constant has been made to reveal the mechanical stability of RuB2 up to 100~GPa.展开更多
The lattice dynamic, elastic, and thermodynamic properties of Be Se were investigated with first principles calculations. The phase transition pressure from the zinc blende（B3） to the nickel arsenide（B8） structure...The lattice dynamic, elastic, and thermodynamic properties of Be Se were investigated with first principles calculations. The phase transition pressure from the zinc blende（B3） to the nickel arsenide（B8） structure of Be Se was determined. The elastic stability analysis suggests that the B3 structure Be Se is mechanically stable in the applied pressure range of 0-50 GPa. Our lattice dynamic calculations show that the B3 structure is lattice dynamically stable under high pressure. Within the quasiharmonic approximation, the thermodynamic properties including the constant volume heat capacity and constant pressure heat capacity are predicted.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 10776022)
文摘The structural, elastic constants and anisotropy of RuB2 under pressure are investigated by first-principles calculations based on the plane wave pseudopotential density functional theory method within the local density approximation （LDA） as well as the generalized gradient approximation （GGA） for exchange and correlation. The results accord well with the available experimental and other theoretical data. The elastic constants, elastic anisotropy, and Debye temperature ／varTheta as a function of pressure are presented. It is concluded that RuB2 is brittle in nature at low pressure, whereas it becomes ductile at higher pressures. An analysis for the calculated elastic constant has been made to reveal the mechanical stability of RuB2 up to 100~GPa.
基金Funded by the National Natural Science Foundation of China(Nos.11447176 and 11447152)the The National Scholastic Athletics Foundation(No.U1230201)the Doctor Foundation of Southwest University of Science and Technology(Nos.13zx7137 and 14zx7167)
文摘The lattice dynamic, elastic, and thermodynamic properties of Be Se were investigated with first principles calculations. The phase transition pressure from the zinc blende（B3） to the nickel arsenide（B8） structure of Be Se was determined. The elastic stability analysis suggests that the B3 structure Be Se is mechanically stable in the applied pressure range of 0-50 GPa. Our lattice dynamic calculations show that the B3 structure is lattice dynamically stable under high pressure. Within the quasiharmonic approximation, the thermodynamic properties including the constant volume heat capacity and constant pressure heat capacity are predicted.
