Collective excitation spectra of one-dimensional electron systems

Abstract

We calculate, within the random-phase approximation, the elementary excitation spectrum of quasi-one-dimensional electron systems as occurring, for example, in semiconductor microstructures. Using multisubband models, we derive and discuss the dispersion relations for both intrasubband and intersubband excitations and consider the mode-coupling e6'ect between them. We show that the depolarization shift correction for the intersubband excitation could be very large, increasing the intersubband collective mode energy substantially above the single-particle intersubband separation, and, thus explaining a puzzling recent far-infrared spectroscopic experimental observation.Recently, there has been increasing theoretical' and experimental interest in quasi-one-dimensional electron systems (1D ES's) based on semiconductor microstruc-

Many-body exchange-correlation effects in the lowest subband of semiconductor quantum wires

“…The V c (q) are the matrix elements of the Coulomb interaction (screened by the static lattice dielectric constant ǫ 0 ), is the one-dimensional Fourier transformation of the Coulomb interaction. [20,21] Here, K 0 (x) is the zeroth-order modified Bessel function of the second kind. [22] For an external confining potential that is parabolic, the self-consistent confining potential (that is, the external confining potential plus the self-consistent Hartree term) gives approximately a square well potential.…”

“…In a pure system, [21,20,28] 12) where the principal value of logarithm (|Im[ln]| < π) should be taken. In evaluating Π 0 (q, ω) for real frequencies, the limit z = ω + i0 + should be taken.…”

“…In (b), we show both the long wavelength result, ω 2 p = nq 2 V c (q)/m, using V c (q) = 2e 2 | ln(qa)|/κ (dotted line) and the full V c (q) (long dashed lines). Experimental results of reference [5] compared with RPA theory (of reference [21]) are shown as an inset in Fig. (a).…”

Collective excitations spectrum of a density modulated quasi-one-dimensional electron gas in a magnetic field

“…In a DM2DEG the number of occupied Landau levels increases with decreasing B, leading, ideally, to an infinite number of SdH type of oscillations periodic in 1/B [23]. In a 1DEG system however, only a finite number of 1D subbands are occupied at B = 0, giving rise to finite number of SdH type of oscillations and deviations from the 1/B period, because with increasing B the 1D density of states increases and the hybrid 1D subband Landau levels are depopulated [4,13,25]. In the extreme 2D regime (ω 0 << ω c ), the Fermi energy goes to the bottom of the 1D Landau subband.…”

Renormalization of Electron Mass by 2D Coulomb Interactions in a Laterally‐Microstructured Silicon Inversion Layer

“…For x -pot > 0, we need to consider another pole of (9). We make the transformation 6 -+ -6 and f + -f in (10) and again obtain (11).…”