Andreev conductance in the d+ id!-wave superconducting states of graphene

Andreev conductance in the d plus id(')-wave superconducting states of graphene

ترابرد کوانتمی در ساختارهای فلز - عادی - ابررسانا - فلز - عادیِ گرافین

 We study the transport of electrons in a graphene NSN structure in which two normal regions are connected by a superconducting strip of thickness d. Within Dirac-Bogoliubov-de Gennes equations we describe the transmission through the contact in terms of different scattering processes consisting of quasiparticle cotunneling, local and crossed Andreev reflections. Compared to a fully normal stru...

Excitation gap of a graphene channel with superconducting boundaries

We calculate the density of states of electron-hole excitations in a superconductor–normal-metal– superconductor SNS junction in graphene, in the long-junction regime that the superconducting gap 0 is much larger than the Thouless energy ET= v /d with v the carrier velocity in graphene and d the separation of the NS boundaries . If the normal region is undoped, the excitation spectrum consists ...

Andreev bound states in high - T c superconducting junctions

The formation of bound states at surfaces of materials with an energy gap in the bulk electron spectrum is a well known physical phenomenon. At superconductor surfaces, quasiparticles with energies inside the superconducting gap ∆ may be trapped in bound states in quantum wells, formed by total reflection against the vacuum and total Andreev reflection against the superconductor. Since an elect...

Tuning the influence of microscopic decoherence on the superconducting proximity effect in a graphene Andreev interferometer.

We discuss transport measurements through graphene Andreev interferometers exhibiting reentrance of the superconducting proximity effect. We observe that at high gate voltage (VBG) the energy dependence of the Andreev conductance oscillations exhibits a scaling in agreement with theoretical expectations, which breaks down at low VBG, when the Fermi energy approaches the charge neutrality point....