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On the energy band structure and the phase transitions in a cuprous chloride crystal
Author(s) -
Rusakov A. P.
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.2220720206
Subject(s) - exciton , condensed matter physics , condensation , phase transition , phase (matter) , electron , dielectric , band gap , anomaly (physics) , effective mass (spring–mass system) , electronic band structure , crystal (programming language) , materials science , physics , thermodynamics , quantum mechanics , optoelectronics , computer science , programming language
To explain the break‐down of the Lyddane‐Sachs‐Teller (LST) relation and the compressibility anomaly for CuCl a new energy band model is proposed to include a small indirect gap comparable to the binding energy of direct excitons. It is found for such a model that the condensation of excitons can result in the break‐down of the LST relation as well as a number of other anomalies of properties, i.e. CuCl is a high‐temperature excitonic dielectric with an effective mass ratio m h / m c ≈ 10 2 of electrons and holes. It is also shown that high pressure can induce a possible excitonic dielectric‐superconductor phase transition.