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SUMMARY:Gigahertz quantized charge pumping - Mr. Mark Blumenthal\, Semicon
 ductor Physics Group (Cavendish Laboratory)
DTSTART:20070115T141500Z
DTEND:20070115T151500Z
UID:TALK6305@talks.cam.ac.uk
CONTACT:K DAS GUPTA
DESCRIPTION:I will discuss another pumping mechanism for single charges\, 
 which does not\nrely on Coulomb blockade of tunnelling. Single electrons a
 re transported\nthrough a periodically formed decoupled quantum dot (QD). 
 The electrons\ntransported can be regarded as particles "surfing" on the t
 ime dependent\npotential of the well generated by the three barriers\, rat
 her than\ntunnelling through the barriers as waves. Two phase-shifted sinu
 soidal\nsignals applied directly to the metallic finger gates on an etched
 \nGaAs/AlGaAs quantum wire\, pump the electrons at frequencies of up to f 
 = 3.4\nGHz\, corresponding to a current level of 0.54 nA. This approach re
 presents\nan alternative path in the realization of a high current high ac
 curacy\nquantum standard for electrical current\n
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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