Angular Momentum Theory and Localized States in Solids. Investigation of Shallow Acceptor States in Semiconductors

Lipari, N. O.; Baldereschi, A.

doi:10.1103/physrevlett.25.1660

Cited by 126 publications

(66 citation statements)

References 15 publications

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“…[9][10][11][12][13] The ground state is fourfold degenerate, and its basis functions are the eigenfunctions of the total angular momentum formed by the vector summation of the spin and the orbital moment of the localized hole. As a result, the matrix elements and the average value of the spin moment operator become coordinate-dependent.…”

Section: Introductionmentioning

confidence: 99%

Dynamical polarization of nuclear spins by acceptor-bound holes in a zinc-blende semiconductor

Kavokin

Koudinov

2013

Phys. Rev. B

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The ground state of an acceptor-bound hole in a zinc-blende semiconductor is formed by four eigenstates of the total angular momentum, which is a vector sum of spin and orbital moment of the hole. As a result, the hyperfine interaction of the hole with lattice nuclei becomes anisotropic and coordinate-dependent. We develop a theory of dynamic polarization of nuclear spins by the acceptor-bound hole, giving full account for its complex spin structure. The rate of hole-nuclear flip-flop transitions is shown to depend on the angle between the total angular momentum of the hole and the position vector of the nucleus with respect to the acceptor center. The resulted spatially inhomogeneous spin polarization of nuclei gives rise to non-equidistant spin splitting of the hole, which can be detected by methods of optical or microwave spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Dynamical polarization of nuclear spins by acceptor-bound holes in a zinc-blende semiconductor

Kavokin

Koudinov

2013

Phys. Rev. B

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“…Indeed, an analogous semiclassical analysis can be carried out for any system with (nearly) degenerate subbands. These bands can be identified with a single band with a SO coupling acting on an effective spin degree of freedom similar to Lipari and Baldareschi's treatment [19] of the multiply degenerate valence band edge in semiconductors with diamond or zinc blende structure. In particular, we expect that our approach can be applied to the interpretation of de Haasvan Alphen experiments on ultrahigh-purity samples [20] that had called in question the established concepts of magnetic breakdown.…”

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confidence: 99%

Anomalous Magneto-oscillations and Spin Precession

Keppeler

Winkler

2002

Phys. Rev. Lett.

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A semiclassical analysis based on concepts developed in quantum chaos reveals that anomalous magneto-oscillations in quasi two-dimensional systems with spin-orbit interaction reflect the nonadiabatic spin precession of a classical spin vector along the cyclotron orbits.If in a solid the spatial inversion symmetry is broken, spin-orbit (SO) interaction gives rise to a finite spin splitting of the energy bands even at magnetic field B = 0. In quasi two-dimensional (2D) systems this B = 0 spin splitting is frequently analyzed by measuring the magnetoresistance oscillations at small magnetic fields B > 0, known as Shubnikov-de Haas (SdH) oscillations. Following a semiclassical argument due to Onsager [1] it has long been assumed [2,3], that the frequencies f SdH ± of these oscillations are proportional to the unequal occupations N ± of the spin-split subbands,where e is the electron charge andh is Planck's constant.Recently, experiments and numerical quantum mechanical calculations have shown that, in general, these oscillations are not simply related to the B = 0 spinsubband densities [4]. However, it has remained unclear when and why Onsager's semiclassical argument fails. Here we use a semiclassical trace formula for particles with spin, which was only lately developed [5,6] in the context of quantum chaos, in order to show that the anomalous magneto-oscillations reflect the nonadiabatic spin precession along the cyclotron orbits. Currently great efforts are made to obtain a deeper understanding of spin-related phenomena in semiconductor quantum structures, in particular due to possible applications in spintronics [7]. While spin is a purely quantum mechanical property with no immediate analogue in classical physics, the present analysis reveals that our understanding of spin phenomena can be greatly improved by investigating equations of motion for a classical spin vector.In the presence of a magnetic field perpendicular to the plane of a 2D electron system the electrons condense in highly degenerate Landau levels that are regularly spaced in energy. With increasing field B these Landau levels are pushed through the Fermi surface causing magnetooscillations which reflect the oscillating density of states (DOS) at the Fermi energy E F , see, e.g., [8]. Onsager's semiclassical analysis of magneto-oscillations was based on a Bohr-Sommerfeld quantization of cyclotron orbits. However, for systems with spin there is no straightforward generalization of Bohr-Sommerfeld quantization [9,10]. The Gutzwiller trace formula [11] provides an alternative and particularly transparent semiclassical interpretation of magneto-oscillations that is applicable even in the presence of SO interaction. Rather than giving individual quantum energies, the trace formula relates the DOS of the quantum mechanical system to a sum over all periodic orbits of the corresponding classical system. As a function of energy E the individual terms oscillate proportional to cos[S(E)/h] where S(E) is the action of the orbit.First we briefly discuss magn...

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“…[4]. The dynamics of spin-3/2 hole systems are determined by the 4 × 4 Luttinger Hamiltonian H [9,17], which, in the spherical approximation, reads…”

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confidence: 99%

Spin Precession and Alternating Spin Polarization in Spin-3/2Hole Systems

2006

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The spin density matrix for spin-3/2 hole systems can be decomposed into a sequence of multipoles which has important higher-order contributions beyond the ones known for electron systems [R. Winkler, Phys. Rev. B 70, 125301 (2004)]. We show here that the hole spin polarization and the higher-order multipoles can precess due to the spin-orbit coupling in the valence band, yet in the absence of external or effective magnetic fields. Hole spin precession is important in the context of spin relaxation and offers the possibility of new device applications. We discuss this precession in the context of recent experiments and suggest a related experimental setup in which hole spin precession gives rise to an alternating spin polarization.PACS numbers: 72.25. Dc, 71.70.Ej, Spin electronics is a quickly developing research area that has yielded considerable new physics and the promise of novel applications [1]. Among the main focuses of spin electronics are semiconductor systems, where ferromagnetic semiconductors and spin polarized transport stand out as major areas of interest. In these fields, the importance of holes as compared with electrons is manifold. Firstly, the compound semiconductors exhibiting ferromagnetism are p-type materials, in which ferromagnetism has been shown to be mediated by the itinerant holes [2]. These materials have also been used as sources of spin-polarized holes, motivating the search for a more complete understanding of hole spin precession and relaxation. Secondly, the spin-Hall effect was first studied in the context of a hole Hamiltonian [3,4] and first observed in a two-dimensional hole gas [5]. With these facts in mind, we devote this Letter to an in-depth study of the spin dynamics of hole systems.The conduction band of common semiconductors like GaAs is described by a spin-1/2 Hamiltonian so that electron spin dynamics are relatively amenable to theoretical investigation. It is well known that for spin-1/2 electrons the spin-orbit interaction can always be written as a wave vector-dependent effective magnetic field [6,7]. Electron spin precession in this effective field, as well as in an external field, has been discussed extensively and is well understood [8]. The spin dynamics of holes, described by an effective spin s = 3/2 [9], have been studied to a lesser extent [10,11]. In general, the coupling of the hole spin and orbital degrees of freedom cannot be written as an effective magnetic field, so the simple picture of a spin precessing around an effective Zeeman field is not applicable to holes. Nevertheless, we will show that the spin dynamics of hole systems can be viewed as a precession, if precession is understood as a nontrivial periodic motion in spin space described by an equation of the type dS dt = i [H, S] for a suitably generalized spin operator S and spin Hamiltonian H. While it has long been known that holes lose their spin information much faster than electrons, to our knowledge a quantitative discussion of hole spin precession based on a firm theoretical footing h...

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Angular Momentum Theory and Localized States in Solids. Investigation of Shallow Acceptor States in Semiconductors

Cited by 126 publications

References 15 publications

Dynamical polarization of nuclear spins by acceptor-bound holes in a zinc-blende semiconductor

Dynamical polarization of nuclear spins by acceptor-bound holes in a zinc-blende semiconductor

Anomalous Magneto-oscillations and Spin Precession

Spin Precession and Alternating Spin Polarization in Spin-3/2Hole Systems

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