Magnetoplasmon excitations in an array of periodically modulated quantum wires

Abstract

Motivated by the recent experiment of Hochgräfe et al., we have investigated the magnetoplasmon excitations in a periodic array of quantum wires with a periodic modulation along the wire direction. The equilibrium and dynamic properties of the system are treated self-consistently within the Thomas-Fermi-Dirac-von Weizsäcker approximation. A calculation of the dynamical response of the system to a far-infrared radiation field reveals a resonant anticrossing between the Kohn mode and a finite-wavevector longitudinal excitation which is induced by the density modulation along the wires. Our theoretical calculations are found to be in excellent agreement with experiment. 73.20.Mf, 73.20.Dx Typeset using REVT E X 1 7

Nonlocal kinetic energy functional for an inhomogeneous two-dimensional Fermi gas

“…(12), is the reason behind the poor description of the surface density profile. Nevertheless, the reasonably good agreement with exact results, along with its simple form, and exceedingly easy numerical implementation, suggest that the 2D TFvW is still a useful tool for the description of inhomogeneous 2D systems, provided one is interested in properties that are relatively insensitive to the local details of the equilibrium spatial density (e.g., total energies, and collective excitations [23][24][25][26]). …”

“…(15), in real space implies that w(η = 0) = 1, which is automatically satisfied by the solution of Eq. (24). Once the solution to Eq.…”

“…Equation (12) has been used to construct the 2D version of the TFDW theory for an inhomogeneous two-dimensional electron gas (2DEG) [12,19], and more recently, to describe the equilibrium properties of a 2D harmonically trapped, spin polarized dipolar Fermi gas [22]. Although the vW term cannot be justified on the basis of a gradient expansion, the 2D TFDW theory was nonetheless successful in various applications to 2DEGs [23][24][25][26].…”

Gradient correction and Bohm potential for two‐ and one‐dimensional electron gases at a finite temperature

“…Of course, the fact that 2 = 0 in the high-frequency regime and in the static ground state ( = 0, → 0) of the 2D system does not mean that there is no quantum non-locality at all. [22,23] For the 2D system in the static case, van Zyl et al [22] consistently introduced the non-vanishing density gradient correction applying the average density approximation, which goes well beyond the LDA, and Trappe et al [23] derived the gradient correction in terms of the effective potential for the DFT formulated as a joint functional of both the single-particle density and the effective potential energy. [36] In Moldabekov et al [8] , the relation between the second-order functional derivative of the non-interacting free energy functional and the dynamic polarization function in the RPA was established in the framework of the QHD model.…”

“…A non-zero leading term of the density gradient correction to the kinetic energy (in contrast to the free energy) for the 2D electron gas at a finite temperature in the semi-classical approximation was obtained by van Zyl et al [21] using the semi-classical expansion of the diagonal Bloch density matrix. Additionally, attempts to go beyond the LDA, for the 2D system, were taken within the so-called average density approximation [22] and the gradient correction in terms of the effective potential energy [23] to mention but a few.…”