Non-reciprocal waves in two-dimensional electron systems with temperature gradient

We demonstrate that the interaction of dc temperature gradient with ac magnetic field in temperature-biased two-dimensional electron systems leads to formation of a new electromagnetic mode, a two-dimensional thermomagnetic wave (2d TMW). This wave is transverse electric and non-reciprocal, and its damping rate can be lower than that of conventional 2d plasma waves. The Q-factor of 2d TMW is independent of the wave vector. Numerical estimates show that in state-of-the-art two-dimensional electrons systems the 2d TMW Q-factor is the order of ${10}^{-3}$. We discuss possible ways to overcome this issue.