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Acceptor Bound Exciton States in High‐Purity CuCl
Author(s) -
Sauder T.,
Stébé B.,
Certier M.
Publication year - 1981
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.2221060131
Subject(s) - exciton , acceptor , valence (chemistry) , atomic physics , ionization , free electron model , valence band , binding energy , chemistry , exchange interaction , ionization energy , electron , band gap , ion , molecular physics , condensed matter physics , physics , organic chemistry , quantum mechanics , ferromagnetism
The magneto‐optical properties of high‐purity CuCl at 4.2 K show that the two lines ν½ (25665.2 cm −1 ) and ν 2 ′(25697.6 cm −1 ) are due to transitions to (or from) excitons bound to the same neutral acceptor, the two holes arising from the lowest Γ 8 valence band. They are attributed, respectively, to the J = 5/5 and J = 1/2 states of the (A 0 , X) complex. These results are explained by the importance of the electron—hole exchange interaction and by a dominant occurrence of the Γ 8 rather than the Γ 7 neutral acceptors. As a consequence, free holes should chiefly arise from the Γ 7 valence band. This is due to the particularly low value of the valence band spin—orbit splitting (Δ SO ≈ 600 cm −1 ), compared to the free‐exciton binding energy ( E X ≈ 1523 cm −1 ) or to the estimated Γ 7 acceptor ionization energy ( E X ≈ 17000 cm −1 ). These conclusions support the previous assignment of line ν 2 (25654 cm −1 ) to a transition between a free Γ 7 hole and a Γ 6 charged exciton X 2 + .