Mesoscopic dots as collective terahertz oscillators

C. Metzner and D. Stehr
Phys. Rev. B 70, 195433 – Published 29 November 2004

Abstract

Electrons confined in a flat semiconductor quantum dot with a parabolic in-plane potential act like a collective many-particle oscillator under coherent intraband excitation. We investigate theoretically the properties of these oscillators under a simultaneous scale transformation of the lateral dimensions and the electron occupation number. As the lateral size increases from a few nm (typical for self-assembled dots) to the mesoscopic regime, the physics of the system is changing qualitatively: Quantization effects gradually lose importance against Coulomb interactions and eventually the electron lake in a mesoscopic dot resembles a classical Wigner liquid. This parabolically confined “Wigner lake” behaves to the outside like a form-elastic “superparticle” of high charge. It can be coherently controlled by THz dipole radiation just like a single electron, but with reduced Brownian diffusion in the phonon heat bath. We propose a flexible method to fabricate single mesoscopic dots of a controlled shape, Coulomb-coupled groups of dots, and almost arbitrary potential landscapes, using current semiconductor technology. As a first example, the collective modes of two Coulomb-coupled superparticles in neighboring dots are calculated. Also, we consider the possibility of steering a superparticle with shaped laser pulses to follow any complex two-dimensional orbit.

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  • Received 28 June 2004

DOI:https://doi.org/10.1103/PhysRevB.70.195433

©2004 American Physical Society

Authors & Affiliations

C. Metzner

  • Institut für Technische Physik I, Universität Erlangen, Erwin-Rommel-Str-1, D91058 Erlangen, Germany

D. Stehr

  • Institut für Ionenstrahlphysik und Materialforschung, Forschungszentrum Rossendorf, P.O. Box 510119, D01314 Dresden, Germany

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Issue

Vol. 70, Iss. 19 — 15 November 2004

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