Giant voltages upon surface heating in normal YBa2Cu3O7−δ films suggesting an atomic layer thermopile

Abstract

Experiments are reported which show that temperature gradients perpendicular to the surface of epitaxial normal conducting YBa2Cu3O7−δ films give rise to large transversal voltages between contacts on the film surface. The temperature gradients have been produced by pulsed laser irradiation and by continuous heating of the films by heater wires. To explain the large lateral voltages, an atomic layer thermopile is proposed, which may be formed by the layered structure of the material.