Thermal Transport as a Probe of the Hidden Rashba Effect in the High Temperature Superconductor YBa₂Cu₃O_6+x

The high temperature superconductor YBa₂Cu₃O_6+x is an example of a Rashba bilayer material. The crystal structure comprises a stack of CuO₂ bilayers, and while each bilayer is inversion symmetric, the individal CuO₂ planes within the bilayers are not. This leads to a so-called hidden spin polarization, in which each layer making up the bilayer has a Rashba coupling constant with opposite sign such that the net spin polarization vanishes. In this talk, I will discuss the origins of the effect in YBa₂Cu₃O_6+x, and show that the measurement of the transverse thermal conductivity in an in-plane magnetic field allows one to make a sensitive measurement of the Rashba coupling.