Localized states in two-dimensional semiconductors doped with magnetic impurities in a quantizing magnetic field

Abstract

A theory of magnetic impurities in a two-dimensional electron gas quantized by a strong magnetic field is formulated in terms of Friedel-Anderson theory of resonance impurity scattering. It is shown that this scattering results in an appearance of bound Landau states with zero angular moment between the Landau subbands. The resonance scattering is spin selective, and it results in a strong spin polarization of Landau states, as well as in a noticeable magnetic field dependence of the g factor and the crystal field splitting of the impurity d levels.

Giant quantum oscillations of nuclear spin relaxation rate in QHE systems with magnetic impurities

“…Since the nuclear spin of the impurity interacts with the localized electron which in our case is s function (m ¼ 0) [10], we would expect the important interaction to be with the localized phonons acting as a breathing modes distortion up to few nearest-neighbor shell around the impurity [11]. The electron-phonon interaction is…”

“…[10]. We have shown there that the resonance impurity scattering results in appearance of bound Landau states with zero momentum between the Landau subbands.…”

“…As an example we consider Fe impurity in GaAs which is known to produce an acceptor level E iek ðd 6 =d 5 Þ well below the bottom of the conduction band [12] and therefore expected to be in the weak scattering limit [10]. The calculated inverse field dependence, T À1 1 is presented in Fig.…”

“…r GM l;l 0 is the dimensionless tensor whose upper indices relate to lattice coordinates while the lower indices relate to the electrons, l ¼ ngm: gm is the localized electron in the nth Landau level with the energy E s bn [10]. Here g ¼ e; t 2 determines the irreducible representation of the crystalline point group for the d states and m enumerates lines of these irreducible representations.…”

“…The localized wave functions and the spectrum obtained from Hamiltonian (1) (for details see, Ref. [10]) will be used in our calculation below.…”