Thermal Hall conductivity of spin liquids at low temperatures*

I will describe results on low-temperature thermal Hall conductivity Kxy of several quantum spin liquids based on honeycomb and triangular lattices, primarilty α-RuCl₃, and Na₂BaCo(PO4)₂. In α-RuCl₃, I will describe recent evidence suggesting the existence of a neutral Fermi surface. Results on the thermal Hall conductivity at temperatures performed at temperatures down to 0.4 K will be presented. The difficult challenges facing Kxy measurements will be discussed.