@article{e4100a2148044a318dbc2649a4eed249,
title = " Specular interband Andreev reflections at van der Waals interfaces between graphene and NbSe 2 ",
abstract = "Electrons incident from a normal metal onto a superconductor are reflected back as holes - a process called Andreev reflection. In a normal metal where the Fermi energy is much larger than a typical superconducting gap, the reflected hole retraces the path taken by the incident electron. In graphene with low disorder, however, the Fermi energy can be tuned to be smaller than the superconducting gap. In this unusual limit, the holes are expected to be reflected specularly at the superconductor-graphene interface owing to the onset of interband Andreev processes, where the effective mass of the reflected holes changes sign. Here we present measurements of gate-modulated Andreev reflections across the low-disorder van der Waals interface formed between graphene and the superconducting NbSe 2. We find that the conductance across the graphene-superconductor interface exhibits a characteristic suppression when the Fermi energy is tuned to values smaller than the superconducting gap, a hallmark for the transition between intraband retro Andreev reflections and interband specular Andreev reflections.",
author = "Efetov, {D. K.} and L. Wang and C. Handschin and Efetov, {K. B.} and J. Shuang and R. Cava and T. Taniguchi and K. Watanabe and J. Hone and Dean, {C. R.} and P. Kim",
note = "Funding Information: D.K.E. acknowledges the support of the FAME Center, sponsored by SRC MARCO and DARPA. P.K. acknowledge support by DOE (DE-FG02-05ER46215) and C.H. is supported by AFOSR (FA2386-13-1-4122). K.B.E. gratefully acknowledges the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST 'MISiS' (Nr. K2-2014-015) as well as of Transregio 12 and Priority Program 1459 'Graphene' of Deutsche Forschungsgemeinschaft. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan. T.T. acknowledges support from a Grant-in-Aid for Scientific Research on Grant 262480621 and on Innovative Areas Nano Informatics (Grant 25106006) from JSPS. J.H. acknowledges the NSF DMR-1122594 grant. Funding Information: The authors gratefully acknowledge fruitful discussions with C. Beenakker, I. Aleiner, L. Levitov, A. McDonald, A. Volkov, P. Jarrillo-Herrero, A. Akhmerov, C. Schoenenberger, M. Devoret and J. Pillet. D.K.E. acknowledges the support of the FAME Center, sponsored by SRC MARCO and DARPA. P.K. acknowledge support by DOE (DE-FG02-05ER46215) and C.H. is supported by AFOSR (FA2386-13-1-4122). K.B.E. gratefully acknowledges the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST {\textquoteleft}MISiS{\textquoteright} (Nr. K2-2014-015) as well as of Transregio 12 and Priority Program 1459 {\textquoteleft}Graphene{\textquoteright} of Deutsche Forschungsgemeinschaft. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan. T.T. acknowledges support from a Grant-in-Aid for Scientific Research on Grant 262480621 and on Innovative Areas Nano Informatics (Grant 25106006) from JSPS. J.H. acknowledges the NSF DMR-1122594 grant. Publisher Copyright: {\textcopyright} 2015 Macmillan Publishers Limited. All rights reserved.",
year = "2016",
month = apr,
day = "1",
doi = "10.1038/nphys3583",
language = "English (US)",
volume = "12",
pages = "328--332",
journal = "Nature Physics",
issn = "1745-2473",
publisher = "Nature Publishing Group",
number = "4",
}