Probing time reversal symmetry breaking topological superconductivity in twisted double layer copper oxides with polar Kerr effect
Abstract
Recent theoretical work predicted emergence of chiral topological superconducting phase with spontaneously broken time reversal symmetry in a twisted bilayer composed of two high-Tc cuprate monolayers, such as Bi2Sr2CaCu2O8+δ. Here we identify large intrinsic Hall response that can be probed through the polar Kerr effect measurement as a convenient signature of the T-broken phase. Our modelling predicts the Kerr angle θK to be in the range of 10-100 μrad, which is a factor of 103-104 times larger than what is expected for the leading chiral supercondutor candidate Sr2RuO4. In addition we show that the optical Hall conductivity σH(ω) can be used to distinguish between the topological dx2-y2 idxy phase and the dx2-y2 is phase which is also expected to be present in the phase diagram but is topologically trivial.