Structural phase transition and elastic properties of thorium pnictides at high pressure

Abstract

In the present paper we have pointed out the weaknesses of the approach by Aynyas et al [1] to study the structural phase transition and elastic properties of thorium pnictides. The calculated values of phase transition pressure and other elastic properties using the realistic and actual approach are also given and compared with the experimental and previous theoretical work.In a paper entitled 'Structural phase transition and elastic properties of thorium pnictides at high pressure', Aynyas et al [1] have calculated the structural and elastic properties of thorium monopnictides at high pressure by using the rigid ion potential model. Though the model used by them is too good and simple to explain these properties and gives values close to the experimental findings, the model theory and method of calculation given by them is neither the realistic nor the actual one. The matching of the results claimed by these workers with the experimental data is rather forced. The weaknesses in the approach of these workers are as follows:The potential used by Aynyas et al isand the expressions of cohesive energies for the B1 and B2 phases are U B1 (r) = −1.7475e 2 Z 2 r + 6X ij (r) + 6X ii (r) + 6X jj (r)and 649

Theoretical investigation of phase transition properties in strontium chalcogenides using potential model

“…For B1 phase, the hardness parameter and the pre-exponential factor b are determined from the thermodynamic condition of bulk modulus B 01 ¼ V 01 ðd 2 U B1 ðrÞ=dV 2 1 Þ r¼r 0 and the equilibrium condition ½dU B1 ðrÞ=dr r¼r 0 ¼ 0, which gives [23,24] …”

Ab initio study of elastic and electronic properties of cubic thorium pnictides ThPn and Th3Pn4 (Pn = P, As, and Sb)

“…Despite a number of interesting results on the physical properties of ThPn and Th 3 Pn 4 materials, the data on their mechanical behavior and electronic properties, to our knowledge, are limited to several early works devoted mainly to mono-pnictides ThPn [5,[9][10][11][12][13][14][15][16][17].…”