Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 5: Quantenpunkte und -dr
ähte: Transporteigenschaften I
HL 5.8: Vortrag
Montag, 24. März 2003, 12:15–12:30, POT/81
Metallic like resistance in a disordered 1D insulator: Effects of finite temperature and decoherence — •Pavel Vagner1,2, Martin Moško2,1, and Thomas Schäpers1 — 1Institut für Schichten und Grenzflächen, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2Institute of Electrical Engineering, Slovak Academy of Sciences, 84239 Bratislava, Slovakia
It is believed, that a disordered one-dimensional (1D) wire with coherent electronic conduction is an insulator with the mean resistance < ρ > ≃ exp(2L/ξ) and resistance dispersion Δρ ≃ exp(L/ξ), where L is the wire length and ξ is the electron localisation length [1]. We show that this 1D insulator undergoes at full coherence the crossover to a 1D “metal”, caused by thermal smearing and resonant tunnelling. As a result, Δρ becomes L/ξ-independent and smaller than unity, while < ρ > grows with L/ξ linearly and eventually polynomially, manifesting the so-called medium localization. A comparison with available experimental data [2] is given.
To address the question how the wire resistance is modified by phase-breaking collisions we have developed a phenomenological model of dephasing. We calculate statistical properties of the wire resistance as a function of the wire length, Thouless coherence length, localization length, and temperature. We trace transition from coherent to incoherent transport at zero and nonzero temperature.
[1] Y. Imry, Introduction to Mesoscopic Physics (Oxford University Press, Oxford, UK, 2002).
[2] D. Kaufman et al., Phys. Rev. B 59, R10433 (1999).