Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 71: Transport Properties
HL 71.6: Talk
Thursday, March 23, 2017, 11:00–11:15, POT 112
Electron pairing in nonlinear nanoelectromechanical systems — •Matthias Droth1, Gábor Széchenyi2, and András Pályi1,2 — 1Budapest University of Technology and Economics (Budapest, Hungary) — 2Eötvös University (Budapest, Hungary)
Despite the success of BCS-theory, the underlying mechanism for electron-pairing remains elusive for many superconducting materials. For SrTiO3, it has been shown [1] that electron-pairing outside the superconducting regime can be explained with an effectively negative charging energy U<0. Here, we show theoretically that a quantum dot on a non-linear mechanical resonator supports electron-pair tunneling through the device by means of U<0 while its system parameters lie within reach of current experiments. We describe the system as a capacitor network model and discuss its relation to the Anderson-Holstein model [2]. Restricting the mechanical resonator potential to quadratic and quartic terms, we find that the system always possesses a phase that supports electron-pair tunneling. This phase can be achieved with a quantum dot on a suspended graphene resonator.
[1] Guanglei Cheng et al., Electron pairing without superconductivity, Nature (London) 521, 196 (2015).
[2] J. Koch, M. E. Raikh, and Felix von Oppen, Pair tunneling through single molecules, Phys. Rev. Lett. 96, 056803 (2006).