Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 6: Postersitzung I (Amorphe- u. Tunnelsysteme, Niedrigdimensionale Systeme, Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter)
TT 6.16: Poster
Montag, 24. März 2003, 14:30–19:00, P2c, P2d
Order parameter phase locking as a cause of a zero bias peak in the differential tunneling conductance of bilayers with electron-hole pairing — •Alexey Bezuglyj1 and Sergey Shevchenko2 — 1NSC Kharkov Institute of Physics and Technology, 61108, Kharkov, Ukraine — 2Institute for Low Temperature Physics and Engineering, 61164, Kharkov, Ukraine
In n-p bilayer systems an exotic phase-coherent state emerges due to by Coulomb pairing of n-layer electrons with p-layer holes. Unlike Josephson junctions, the order parameter phase may be locked by matrix elements of interlayer tunneling in n-p bilayers and we show how the phase locking phenomenon specifies response of the electron-hole condensate to interlayer voltages. Without applied magnetic field, the phase is steady-state (locked) at small interlayer voltages, V<Vc, however the phase increases monotonically with time (is unlocked) at V>Vc. The change of the system dynamics at V=Vc leads to a peak in the differential tunneling conductance. The peak width Vc is proportional to the absolute value of the tunneling matrix element |T12| but its height does not depend on |T12|; thus the peak is sharp for small |T12|. Sufficiently strong in-plane magnetic field reduces considerably the peak height. These results agree qualitatively with zero bias peak behaviour which was recently observed in quantum Hall bilayer ferromagnets.