Excitonic BEC in

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Excitonic BEC in in Quantum Hall Bilayers
May 2005
Ramin Abolfath NRCC Anton Burkov UCSB
Jim Eisenstein Cal Tech. Steve Girvin
Yale Yogesh Joglekar LANL Jairo Sinova Texas
AM Ady Stern Weizmann Leo Radzihovsky
UC Alvaro Nunez UTA Enrico Rossi
UTA Giovanni Vignale UMC
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Reference
Eisenstein and AHM Nature 432, 691 (2004)
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Josephson Qubit
Non-linear Non-Dissipative
Devoret Walraff Martinis cond-mat/0411
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Landau Liftshitz Gilbert
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Excitons Elementary Excitations of Intrinsic
Semiconductors
Conduction Band
e
h
h
Valence Band
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Excitonic BEC and Superfluidity?
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Electron-Hole Pairs
(n,n)(?,?) Ferromagnetism (n,n)(c,v)
Excitonic BECs (n,n)(TopLayer,BottomLayer)
Order Parameter
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Quantum Wells
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Molecular Beam Epitaxy
heated cells

Al
Ga
As
Pfeiffer - Bell Labs Shayegan Princeton
ultra high vacuum
high quality GaAs substrate
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Electrons and Holes in the QH Regime
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0
0
voltmeter
voltmeter
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Electron-hole Pair Current
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Superflow in Electron-Electron Bilayers
Hall Angle Not Large
sxx ? 1000 e2/h
Kellogg and Eisenstein cond-mat/0401521
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Josephson-like Currents
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Josephson Effect
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Collective Dynamics Dissipation
Ferromagnets vs. Josephson Junctions vs. Bilayers
J.J. Dynamics
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Joglekar TDHFASCBA
? af gtgt aN
Joglekar AHM PRB (2002)
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Thin Film Ferromagnets
Buhrman Ralph, MSU, NIST, Orsay
Spin Transfer
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Coherent Edge Transport
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Excitonic Bose Einstein Condensation in Quantum
Hall Bilayers ! Macroscopic Quantum
Coherence properties different from both JJs and
thin film magnets