Thermoelectric response as a tool to observe electrocaloric effect in a thin conducting ferroelectric SnSe flake

We experimentally investigate thermoelectric response of a 100~nm thick SnSe single crystal flake under the current-induced dc electric field. Thermoelectric appears as second-harmonic transverse voltage $V_{xy}^{2\omega}$, which reflects temperature gradient across sample due to Joule heating by harmonic ac excitation current $I_{ac}$. In addition strongly non-monotonous dependence we observe that field direction controls sign in flake. provide arguments, electrocaloric effect is mostly probable reason for results obtained. Thus, our experiment can be understood demonstration possibility induce in-plane conducting ferroelectric crystals and detect it response.