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Ground‐state properties of Cd x Sn 1– x Te: The role of d ‐electrons
Author(s) -
Grosch G. H.,
Freytag B.,
Range K.J.,
Rössler U.
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560520417
Subject(s) - electron , ground state , core electron , bulk modulus , condensed matter physics , density functional theory , lattice constant , chemistry , electronic structure , local density approximation , crystal (programming language) , physics , atomic physics , quantum mechanics , computational chemistry , diffraction , computer science , programming language
Within the framework of density functional theory ( DFT ), we calculate the ground‐state electronic properties of Cd x Sn 1– x Te using norm‐conserving pseudopotentials in connection with the local density ( LDA ) and virtual crystal approximation ( VCA ). Our particular interest is in the influence of the Cd‐4 d and the Sn‐4 d electrons by comparing results obtained with pseudopotentials, which either consider the d ‐electrons explicitly or in the frozen core.In the mixed crystal system Cd x Sn 1– x Te, the transition from a ten‐ ( x = 0) to an eight‐electron ( x = 1) system is realized, which is accompanied by a change of the crystal structure from rock salt (SnTe) to zinc blende (CdTe). By calculating the ground‐state energies, we find the equilibrium lattice constant as the function of x and the bulk modulus, as well as the crossover value of x for the transition from rock‐salt to zinc blende. The calculated lattice constants and bulk moduli are in much closer agreement with experimental data if the d ‐electrons are taken into account explicitly, whereas the crossover is rather insensitive with respect to the d ‐electrons. In view of the electronic charge density, we demonstrate the decrease of ionicity for increasing x . © 1994 John Wiley & Sons, Inc.