Phase transition properties of SmTe under pressure

Abstract

Phase transition properties of SmTe under high pressure have been investigated through ab initio pseudo-potential calculations within the framework of density functional theory. Local density approximation based on exchange-correlation energy optimization has been used for calculating the total energy of the system. The calculated equilibrium lattice constant, bulk modulus and its pressure derivative agree well with the experimental data. The first-principles studies of isostructural valence transition from Sm 2þ to Sm 3þ in B1 phase (Fm " 3m) and from B1 ! B2 phase transition characterized by the space group Pm " 3m in bulk SmTe have been carried out. The calculated transition pressure, equation of state and volume collapse show good agreement with experimental results. Under ambient conditions, the energy of Sm 2þ in B1 phase is found to be lower than that of Sm 3þ . At high pressures beyond B1 ! B2 phase transition, the energy of B2 phase is found to be slightly lower than that in B1 phase.

Pressure induced magnetic, electronic and mechanical properties of SmX (X = Se, Te)

“…The phase transition properties of SmTe have been computed by SIESTA within LDA [28] and the results obtained were in good agreement with the experimental data [5,8] and better than those obtained by others [19]. This encouraged us to take up the present study with the spin-polarized generalized gradient approximation (GGA) because these materials are strongly correlated in nature and hence spin is considered for studying magnetic properties.…”

“…Rare-earth compounds (RECs) have attracted experimental [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and theoretical attention [17][18][19][20][21][22][23][24][25][26][27][28] due to the presence of strongly correlated electrons in them. They possess interesting structural, mechanical, magnetic, magneto-optic and electronic properties which make them candidates for industrial and technological applications.…”

Strategies and challenges of high-pressure methods applied to thermoelectric materials

“…2(b)]. 28 For the original phase of SmTe that is stable below 4 GPa and has a bulk modulus B 0 ∼ 40 GPa, 36 Eq. (2) does indeed describe the pressure dependence of the thermal conductivity, but with a much lower parameter w, of about 5.4 and 2.7 for samples 1 and 2, respectively.…”