標題: Carrier density dependent electric transport of serially connected two quantum point contacts
作者: Liu, K. M.
Lin, H. I.
Umansky, V.
Hsu, S. Y.
電子物理學系
Department of Electrophysics
關鍵字: Quantum point contacts in series;Transmission probability;Adiabatic transport;Ohmic transport
公開日期: 1-二月-2010
摘要: We have measured the electric transport of double quantum point contacts in series at low temperatures. Two pairs of metal gates are placed longitudinally and sequentially with an edge-to-edge distance of 600 nm. They are used to form two quantum point contacts in a GaAs/Al(x)Ga(1-x)As heterostructure. Isolating from an insulating layer, a top gate is also fabricated on top of the quantum point contacts to modify the electron densities in the quantum point contacts and the two dimensional electron gas as well. The transport is characterized by the direct transmission probability T(d) which represents the portions of electrons travelling ballistically from one quantum point contact to the other. Our results show that the parameter T(d) decreases with decreasing carrier density. The transport is partially adiabatic in high 20 electron densities and transits to completely ohmic regimes in low densities. Because of the correlation between the coherence length and transmission probability, we attribute the result to the reduction of the coherence length and mean free path in the unconstricted electron gas between quantum point contacts. (C) 2010 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.physe.2009.11.094
http://hdl.handle.net/11536/12456
ISSN: 1386-9477
DOI: 10.1016/j.physe.2009.11.094
期刊: PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
Volume: 42
Issue: 4
起始頁: 1122
結束頁: 1125
顯示於類別:會議論文


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