Strain-induced time-reversal odd superconductivity in graphene

I will discuss the possibility of realizing a time-reversal-symmetry breaking superconducting state that exhibits an $f+is$ pairing symmetry in strained graphene [1]. Although the underlying attractive interactions need to be sufficiently strong and comparable in pristine graphene to support such pairing state, I will argue that strain can be conducive for its formation even for weak interactions. I will show that quantum-critical behavior near the transition is controlled by a fermionic multicritical point, characterized by various critical exponents computed in the framework of an $\epsilon$-expansion near four spacetime dimensions. I will then discuss the scaling of the superconducting gap with the strain-induced axial pseudo-magnetic field. Furthermore, a vortex in this mixed superconducting state hosts a pair of Majorana fermions supporting a quartet of insulating and superconducting orders, among which quantum spin Hall topological insulator. Finally, I will mention some experimental signatures of this $f+is$ time-reversal odd superconductor. These findings suggest that strained graphene could provide a platform for the realization of exotic superconducting states of Dirac fermions.\\[4pt] [1] B. Roy and V. Juricic, arXiv: 1309.0507.