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Temperature Dependence of Core and Valence Thermal Vibrations in Germanium
Author(s) -
Jeyakanthan J.,
Saravanan R.,
Mohanlal S. K.
Publication year - 1995
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221900210
Subject(s) - anharmonicity , valence (chemistry) , core electron , thermal , polarizability , vibration , germanium , valence electron , electron , amplitude , atomic physics , debye model , materials science , core (optical fiber) , phase (matter) , condensed matter physics , molecular physics , chemistry , physics , thermodynamics , optics , molecule , silicon , quantum mechanics , composite material , organic chemistry , metallurgy
An X‐ray analysis is made for the core and valence thermal vibrations in germanium, using powder X‐ray intensity data collected at various temperatures (298, 573, and 733 K). The overall thermal vibration is split into the components of core and valence thermal vibrations, because the valence electrons oscillate with different phase and amplitude than the core electrons due to bond polarizability. The data collected at the above temperatures are analyzed using locally developed computer programs. In the first phase, the overall Debye‐Waller factors are estimated. Then in the second phase, the core and valence contributions of the thermal vibrations are refined. The error in the fitting procedure is found to be less than 2%, and in the third phase an attempt is made to refine the individual anharmonic thermal parameters (β core and β val ), which result in unrealistic thermal parameter values. Hence only the overall anharmonic thermal parameters are evaluated and the results are reported.