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Δ M = 3 Spin‐flip acceptor scattering and zerofield splittings
Author(s) -
Scott J. F.,
Handschy M. A.
Publication year - 1985
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250160508
Subject(s) - acceptor , hamiltonian (control theory) , polarizability , condensed matter physics , spin flip , scattering , atomic physics , chemistry , gyromagnetic ratio , physics , magnetic field , magnetic moment , quantum mechanics , mathematical optimization , mathematics , molecule
Abstract In the presence of an external magnetic field, shallow acceptor levels in II‐VI semiconductors split into a J =3/2 quartet of nearly evenly spaced levels. At cryogenic temperatures only the M J = −3/2 state is thermally occupied, and two transitions are expected: Δ M = 1 (−3/2 to −1/2) with α xx and α xy polarizabilities (z is the direction of applied field) and Δ M =2 (−3/2 to +1/2) with α xz and α yz polarizabilities. In addition to those transitions we have observed at high magnetic fields ( H ⩽4T) a third transition with α xx and α xy polarizability; we assign it as Δ M = 3 and show that although it is strictly forbidden in zero field, its cross‐section varies theoretically as H 2 , and experimentally it becomes comparable in intensity to the Δ M = 2 transition in both ZnTe: Li and ZnTe: Ag at 10 T. This analysis allows a more accurate evaluation of the gyromagnetic ratio g = − 2 k =0.567 ± 0.025 and of the crystal field parameter q̃ in the spin Hamiltonian of Zn Te: Li as q̃ = −0.012±0.006; the sign and magnitude of q̃ have previously been in doubt and can be different for different acceptors. Non‐zero spin‐flip energies are found, interpreted as due to strain or exchange. These appear to vary with acceptor concentration, and are E 1/2 = 1.45± 0.29 cm −1 and E 3/2 =4.39±0.14 cm −1 for 0.01% Li. The fact that E 3/2 ≈ 3 E 1/2 indicates that the mean field approximation is valid, with an effective field in zero external magnetic field of H e ≈ 3.5 T.