Probing Time Reversal Symmetry Breaking Topological Superconductivity in Twisted Double Layer Copper Oxides with Polar Kerr Effect

Recent theoretical work predicted the emergence of a chiral topological superconducting phase with spontaneously broken time reversal symmetry in a twisted bilayer composed of two highTc cuprate monolayers such as Bi2Sr2CaCu2O8+δ . Here, we identify a large intrinsic Hall response that can be probed through the polar Kerr effect measurement as a convenient signature of the T -broken phase. Our modeling predicts the Kerr angle θK to be in the range of 10 – 100 μ rad, which is a factor of 103 to 104 times larger than what is expected for the leading chiral superconductor candidate Sr2RuO4. In addition, we show that the optical Hall conductivity σH( ω ) can be used to distinguish between the topological dx2−y2 ± i dxy phase and the dx2−y2 ± i s phase, which is also expected to be present in the phase diagram but is topologically trivial.