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Contribution of Lattice Dilation to the Temperature Shift of the Energy Gaps in Trigonal Selenium
Author(s) -
Lingelbagh W.,
Weiser G.
Publication year - 1975
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.2220700205
Subject(s) - condensed matter physics , nearly free electron model , trigonal crystal system , phonon , band gap , perpendicular , lattice (music) , materials science , hexagonal lattice , dilation (metric space) , temperature coefficient , thermal , chemistry , particle in a one dimensional lattice , physics , optics , crystal structure , crystallography , thermodynamics , diffraction , geometry , mathematics , reciprocal lattice , antiferromagnetism , acoustics , composite material
The influence of thermal lattice dilation on the temperature shift of some optical transitions has been studied. Below 100 K the shift of both the direct gap at H and the indirect gap is determined by the lattice dilation perpendicular to the hexagonal axis c , caused by acoustical phonons which leads to an increase of the gap energy with rising temperature. At higher temperatures the electron‐phonon coupling (mainly by optical phonons) gains importance and decreases the temperature coefficient of the gap energies. The energy of the direct gap at Z is less sensitive to the thermal dilation of the lattice.