title: Andreev Reflection in an s-Type Superconductor Proximized 3D Topological Insulator.
abstract: We investigate transport and shot noise in lateral normal-metal-3D topological-insulator-superconductor contacts, where the 3D topological insulator (TI) is based on Bi. In the normal state, the devices are in the elastic diffusive transport regime, as demonstrated by a nearly universal value of the shot noise Fano factor F_{N}≈1/3 in magnetic field and in a reference normal-metal contact. In the absence of magnetic field, we identify the Andreev reflection (AR) regime, which gives rise to the effective charge doubling in shot noise measurements. Surprisingly, the Fano factor F_{AR}≈0.22±0.02 is considerably reduced in the AR regime compared to F_{N}, in contrast to previous AR experiments in normal metals and semiconductors. We suggest that this effect is related to a finite thermal conduction of the proximized, superconducting TI owing to a residual density of states at low energies.
authors.affiliation: Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russian Federation.|Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Russian Federation.
authors.forename: E S
authors.initials: ES
authors.lastname: Tikhonov
authors.affiliation: Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russian Federation.|Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Russian Federation.
authors.forename: D V
authors.initials: DV
authors.lastname: Shovkun
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Snelder
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: M P
authors.initials: MP
authors.lastname: Stehno
authors.affiliation: Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: M S
authors.initials: MS
authors.lastname: Golden
authors.affiliation: Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Russian Federation.|MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: Golubov
authors.affiliation: MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Brinkman
authors.affiliation: Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russian Federation.|Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Russian Federation.
authors.forename: V S
authors.initials: VS
authors.lastname: Khrapai