Effect of proximity-induced spin-orbit coupling in graphene mesoscopic billiards

van der Waals heterostructures based on two-dimensional materials have recently become a very active topic of research in spintronics, both aiming at a fundamental description of spin dephasing processes in nanostructures and as a potential element in spin-based information processing schemes. Here, we theoretically investigate the magnetoconductance of mesoscopic devices built from graphene proximity-coupled to a high spin-orbit coupling material. Through numerically exact tight-binding simulations, we show that the interfacial breaking of inversion symmetry generates robust weak antilocalization even when the z → −z symmetric spin-orbit coupling in the quantum dot dominates over the Bychkov-Rashba interaction. Our findings are interpreted in the light of random matrix theory, which links the observed behavior of quantum interference corrections to a transition from a circular-orthogonal to circular-symplectic ensemble.