Phase-coherent electron transport in asymmetric crosslike Andreev interferometers

Physical Review B: Condensed Matter and Materials Physics. 2019. Vol. 100. No. 054511. P. 1–11.

Dolgirev P. E., Kalenkov M. S., Tarkhov A., Zaikin A.

We present a detailed theoretical description of quantum coherent electron transport in voltage-biased
crosslike Andreev interferometers.Making use of the charge conjugation symmetry encoded in the quasiclassical
formalism, we elucidate a crucial role played by geometric and electron-hole asymmetries in these structures.
We argue that a nonvanishing Aharonov-Bohm-like contribution to the current IS flowing in the superconducting
contour may develop only in geometrically asymmetric interferometers making their behavior qualitatively
different from that of symmetric devices. The current I_N in the normal contour—along with I_S—is found to be
sensitive to phase-coherent effects thereby also acquiring a 2π-periodic dependence on the Josephson phase.
In asymmetric structures this current develops an odd-in-phase contribution originating from electron-hole
asymmetry. We demonstrate that both phase-dependent currents I_S and I_N can be controlled and manipulated
by tuning the applied voltage, temperature, and system topology, thus rendering Andreev interferometers
particularly important for future applications in modern electronics.

Keywords: proximity effect, mesoscopic superconductivity, мезоскопическая сверхпроводимость, квантовая когерентность, quantum coherence, эффект близости