Conductance G of a 2DEG-Superconductor (S) device in a high magnetic field is studied: G(ν) is calculated. When the cyclotron diameter in 2DEG is larger than the width of the 2DEG-S surface then G(ν) becomes nonmonotonous function due to the Aharonov-Bohm type interference of quasiparticles at the surface. At certain parameters of the junction the conductance oscillates with ν. : 74.80.Fp, 71.70.Di, In recent years, the study of hybrid systems consisting of superconductors in contact with normal metals in strong magnetic field has attracted considerable interest [1] - [5]. Investigation of physical phenomena in S-2DEG devices in high magnetic field may help to establish a link between mesoscopic superconductivity and quantum -Hall physics. It was found experimentally [1] that zero-bias conductance G of a ballistic S -2DEG -S junction in Integer Quantum Hall (IQH) regime exhibits quantization under variation of magnetic field. The quantum of G was not equal to a universal value in this experiment, as for instance in IQH or in a quantum point contact [7], but it was an oscillating function of the field H. Numerical simulations [4], [5] showed that the conductance of a 2DEG-S contact in IQH regime is a nonmonotonous function of the filling factor ν; there is nonuniversal quantization of G when 2DEG-S boundary is perfect [6]; at specific range of magnetic field G(ν) oscillates. A phenomenological theory of the conductance oscillations was suggested in [5]. But, it is still unclear when the conductance becomes sensitive to H, why it exhibits oscillations, how one can analytically describe G(H). The analytical form of G(ν) is found in this paper. It is shown that the conductance becomes sensitive to H when 2R c L, where R c is a cyclotron radius in 2DEG, L characterizes the length of the 2DEG-S boundary; nonlinearities of G(ν) result from Aharonov-Bohm type interference of quasiparticles at the boundary.
PACSWe consider a junction consisting of a superconductor, 2DEG and a normal conductor segments (see Fig.1). Magnetic field H is applied along z direction, perpendicular to the plain of 2DEG. It is supposed that quasiparticle transport is ballistic (the mean free path of an electron l tr ≫ L, where L is the length of the 2DEG-S boundary). The current I is supposed to flow between normal (N) and superconducting (S) terminals (the voltage V is applied between them). The conductance G(H, L) = I/V, V → 0 is studied in the paper.Following [8], we shall describe transport properties of the junction in terms of electron and hole quasiparticle scattering states, which satisfy Bogoliubov-de Gennes (BdG) equations. Then the conductance: Chtchelkatchev N.M. Conductance of a Semiconductor-Superconductor junction in high magnetic field 1