A Ballistic Graphene Cooper Pair Splitter

Abstract

We report an experimental study of Cooper pair splitting in an encapsulated graphene based multiterminal junction in the ballistic transport regime. Our device consists of two transverse junctions, namely the superconductor/graphene/superconductor and the normal metal/graphene/normal metal junctions. In this case, the electronic transport through one junction can be tuned by an applied bias along the other. We observe clear signatures of Cooper pair splitting in the local as well as nonlocal electronic transport measurements. Our experimental data can be very well described by using a modified Octavio-Tinkham-Blonder-Klapwijk model and a three-terminal beam splitter model.

Electrically controlled crossed Andreev reflection in two-dimensional antiferromagnets

“…Superconductors may serve as a natural source of entangled electrons [5][6][7][8][9][10]. Electrons in a Cooper pair can be spatially separated, but remain spin and momentum entangled via a process called Cooper pair splitting [11][12][13]. The time-reversal counterpart of this process is known as crossed Andreev reflection (CAR) or nonlocal Andreev reflection.…”

“…To date, numerous superconducting heterostructures have been proposed to enhance CAR signals utilizing different leads, such as normal metals (NMs) [16][17][18], ferromagnetic (FM) metals [15,[19][20][21][22], two-dimensional (2D) graphene layers [23,24], and topological insulators [25][26][27][28][29][30]. Conclusive experimental detection of CAR signals remains challenging, but progress has been made by utilizing NM leads [31][32][33][34][35][36], FM leads [37][38][39][40][41], quantum dots [8,[42][43][44][45][46][47], and very recently, graphene-based systems with opposite doping levels in the two leads [11,48]. Nevertheless, most proposals require fine-tuning of the elec-tronic structure and bias voltage.…”