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arXiv · 2103.10445

Probing time reversal symmetry breaking topological superconductivity in twisted double layer copper oxides with polar Kerr effect

Oguzhan Can·Xiao-Xiao Zhang·Catherine Kallin·Marcel Franz
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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-$T_c$ cuprate monolayers, such as Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$. Here we identify large intrinsic Hall response that can be probed through the polar Kerr effect measurement as a convenient signature of the $\mathcal{T}$-broken phase. Our modelling predicts the Kerr angle $θ_K$ to be in the range of 10-100 $μ$rad, which is a factor of $10^3-10^4$ times larger than what is expected for the leading chiral supercondutor candidate Sr$_2$RuO$_4$. In addition we show that the optical Hall conductivity $σ_H(ω)$ can be used to distinguish between the topological $d_{x^2-y^2}\pm id_{xy}$ phase and the $d_{x^2-y^2}\pm is$ phase which is also expected to be present in the phase diagram but is topologically trivial.

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Oguzhan Can, Xiao-Xiao Zhang, Catherine Kallin, Marcel Franz. 2021-03-18. Probing time reversal symmetry breaking topological superconductivity in twisted double layer copper oxides with polar Kerr effect. https://doi.org/10.1103/physrevlett.127.157001

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