Observation of magnetoplasmons, rotons, and spin-flip excitations in GaAs quantum wires

Goñi, A. R.; Pinczuk, A.; Weiner, J. S.; Bs, Dennis; Pfeiffer, L. N.; West, K.W.

doi:10.1103/physrevlett.70.1151

Cited by 68 publications

(26 citation statements)

References 13 publications

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“…In the presence of weak disorder we expect that the processes leading to the Coulomb gap interact with the Bragg scattering leading to a gap in the DOS of a Wigner crystal. Such a spin-polarized system of electrons can be realized in organic chains [1] or in quasi-one-dimensional quantum wires in a strong magnetic field [13]. We find in the quantum regime that the DOS can be fitted well with a power-law, and that the exponent decreases as the strength of disorder is increased.…”

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confidence: 82%

“…In this work we employ a self-consistent Hartree-Fock (HF) method to investigate the DOS at zero temperature in the quantum regime where the localization length is comparable to or larger than the inter-particle distance [10]. Both the long-range Coulomb interaction and disorder are expected to reduce quantum fluctuations: The Coulomb interaction pushes the system to the classical limit, where quantum fluctuations can be neglected except for the redefinition of the strength of the impurity potential [11], and disorder is expected to restore the Fermi liquid behavior [12,13]. Thus a HF mean-field approximation may provide a reasonable description of the interplay between disorder and the Coulomb interaction [14].…”

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confidence: 99%

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Coulomb gaps in one-dimensional spin-polarized electron systems

1996

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We investigate the density of states (DOS) near the Fermi energy of one-dimensional spinpolarized electron systems in the quantum regime where the localization length is comparable to or larger than the inter-particle distance. The Wigner lattice gap of such a system, in the presence of weak disorder, can occur precisely at the Fermi energy, coinciding with the Coulomb gap in position. The interplay between the two is investigated by treating the long-range Coulomb interaction and the random disorder potential in a self-consistent Hartree-Fock approximation. The DOS near the Fermi energy is found to be well described by a power law whose exponent decreases with increasing disorder strength. The effects of electron interactions are particularly strong in one-dimensional (1D) systems, leading to Luttinger liquids or to various instabilities [1]. Random disorder also has strong effects in 1D systems: Regardless of disorder strength, all states are known to be localized with the localization length comparable to the mean free path [2]. The interplay of electron interactions and random disorder in low-dimensional systems is of great current interest [3,4]. It has been shown recently that in the absence of disorder the long-range Coulomb interaction between electrons reduces quantum fluctuations so that the ground state acquires quasi-long range order much close to a 1D Wigner crystal [5]. This reduction of quantum fluctuations is reflected in the density of states (DOS), which vanishes faster than any power as the Fermi energy µ is approached [5,6]:where A and E c are appropriate constants. In the strongly localized regime, where the overlap of electron wave functions is negligible, electrons may be treated classically and the DOS exhibits a Coulomb gap of the form [7]:When the Thouless length is shorter than the localization length, the system is in the disordered Fermi liquid regime, where the overlap of electron wave functions can be significant. In this case the electron interactions can be included perturbatively within the weak localization theory [8], and the first-order correction to the DOS near the Fermi level is given by [9] δg(E) ∼ |E − µ|except in the limit E → µ, where the perturbation theory is expected to breakdown.In this work we employ a self-consistent Hartree-Fock (HF) method to investigate the DOS at zero temperature in the quantum regime where the localization length is comparable to or larger than the inter-particle distance [10]. Both the long-range Coulomb interaction and disorder are expected to reduce quantum fluctuations: The Coulomb interaction pushes the system to the classical limit, where quantum fluctuations can be neglected except for the redefinition of the strength of the impurity potential [11], and disorder is expected to restore the Fermi liquid behavior [12,13]. Thus a HF mean-field approximation may provide a reasonable description of the interplay between disorder and the Coulomb interaction [14]. This interplay is especially interesting with spin-polarized electrons since th...

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confidence: 82%

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confidence: 99%

Coulomb gaps in one-dimensional spin-polarized electron systems

1996

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“…Sakaki 9 calculated, that for 1D GaAs channels the electron mobility exceeds 10 6 cm 2 /V at low temperature, which is more than one order of magnitude larger than the calculated electron mobility of a two-dimensional electron gas. 10 The effect of quantum confinement in quantum wires ͑QWR's͒ has been evidenced in the luminescence, [11][12][13] two-photon optical absorption, 14 inelastic light scattering, 15 and various other studies. It is obvious that impurity scattering and boundary effects become increasingly important when the width of the QWR's is reduced.…”

Section: Introductionmentioning

confidence: 99%

Fullerene-structured nanowires of silicon

1999

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Silicon vapor from a magnetron sputter source was deposited onto highly oriented pyrolytic graphite, resulting in the formation of nanoscale wires. The structures were analyzed by scanning tunneling microscopy. The wires are from 3 to 7 nm in diameter and at least 100 nm long. They tend to be assembled parallel in bundles. In order to understand the observed quasi-one-dimensional structures, diamondlike and fullerenelike wire models are constructed. Molecular-orbit calculations yield binding energies and band gaps of such structures, and lead us to propose a fullerene-type Si 24 -based atomic configuration for nanowires of silicon.

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“…The SCF treatment presented here is by its nature a high density approximation which has been successful in the study of collective excitations in lower-dimensional systems such as planar semiconductor superlattices [17] and quantum wire structures [5,8,18], both with and without an applied magnetic field. Such success has been convincingly attested by the excellent agreement of SCF predictions of plasmon spectra with experiments.…”

Section: Density-density Correlation Function Of a Dm1deg In A Mmentioning

confidence: 99%