Andreev reflection and 0- π transition in graphene-based antiferromagnetic superconducting junctions

Abstract

We investigate the Andreev reflection and 0-π transition in the graphene-based antiferromagnetic superconducting junctions on the SiC substrate, respectively. The differential conductance of Andreev reflection is reduced in the presence of a gap induced by the antiferromagnet or the substrate. Interestingly, although the gap induced by the antiferromagnet is the same to the one induced by the substrate, their differential conductances of the Andreev reflection are absolutely different, which can be used to detect antiferromagnetism in experiment. Although the interaction between the antiferromagnet and the substrate cannot show special differential conductance, their interaction can bring the 0-π transition. This breaks up the conventional wisdom that the antiferromagnetism-induced 0-π transition shows a rigorous atomic-scale dependence on the interlayer thickness. Furthermore, compared with the conventional atomic-scale dependent 0-π transition, our finding can be realized more easily in the experiment.

Néel proximity effect at antiferromagnet/superconductor interfaces

“…Nevertheless, unconventional Andreev reflection and bound states at such S/AF interfaces have been predicted [13,14]. The rich Josephson physics in S/AF/S hybrids has also been investigated, theoretically [15][16][17][18] and experimentally [19][20][21].…”

Magnetic control of superconducting heterostructures using compensated antiferromagnets

“…Also, the magnetic moments of the antiferromagnet are insensitive to disturbing magnetic fields [20]. Studies of quasiparticle reflection [21,22], Josephson effects [23][24][25][26][27][28], the superconducting critical temperature [29][30][31][32] and the critical field [32] in superconductor-antiferromagnet structures have proven antiferromagnets to be applicable for manipulating the superconducting state, despite their zero net magnetization. Many of these works have focused on uncompensated antiferromagnets with an effective magnetization at the interface, but progress has also been made within research on compensated interfaces.…”

Electrically controlled crossed Andreev reflection in two-dimensional antiferromagnets

“…Recently, the potential of using antiferromagnets in superconducting spintronics has been recognized. For instance, at the interface between an antiferromagnet and a superconductor, normal reflection and AR have been demonstrated to be both specular and retroreflective [49][50][51][52][53][54][55][56][57][58][59][60][61][62]. In heterostructures, these anomalous processes fundamentally change the behaviour of the electrical and thermal conductance [49].…”

“…In heterostructures, these anomalous processes fundamentally change the behaviour of the electrical and thermal conductance [49]. In Josephson junctions, atomic-scale 0 − π transitions [51][52][53][54][55][56] are predicted to occur. The existence of Josephson effects has been experimentally verified [57][58][59][60][61][62], but the remaining theoretical predictions have yet to be explored.…”