On the crossover of the surface plasmon spectrum from two-dimensional to quasi one-dimensional in a quantum point contact

• Published in: Physica. B, Condensed matter Vol. 253; no. 3; pp. 169 - 179
• Main Authors: Aronov, I.E, Berman, G.P, Campbell, D.K, Doolen, G.D, Dudiy, S.V
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.1998; Elsevier
• Subjects: Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Collective excitations (including plasmons and other charge-density excitations); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Quantum point contact; Surface and interface electron states; Surface plasmon spectrum; 72.10.Bgn; Surface plasmon spectrum; Quantum point contact; 05.60; 72.30; Two-dimensional systems; Quantum dots; Dispersion relations; Theoretical study; Quantum point contacts; Surface plasmons; One-dimensional systems
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(98)00406-2

Using a Wigner distribution function formalism, the spectrum of the surface plasmons in a two-dimensional quantum point contact of a strip form is investigated. A crossover of the dispersion relation from 2D plasmons to quasi-1D plasmons is analyzed as a function of two dimensionless parameters: k x d (where k x is the longitudinal wave vector, and d is the width of the contact), and the number of propagating electron modes, N . The velocities of the surface plasmons are calculated. It is shown that in the quasi-1D limit, the spectrum of plasmons is of an acoustic type, and the velocities may greatly exceed the Fermi velocity. When the number of propagating modes N increases, and under the condition k x d≫1 (2D limit), the spectrum of plasmons transforms to the square-root type.