We phenomenologically formulate and experimentally observe an adiabatic transverse thermoelectric conversion enhanced by a heat current reorientation in artificially tilted multilayers (ATMLs). By alternately stacking two materials with different thermal conductivities and rotating the multilayered structure with respect to a longitudinal temperature gradient, we induce off-diagonal components in the thermal conductivity tensor. This off-diagonal thermal conduction (ODTC) generates a finite transverse temperature gradient and Seebeck effect–induced thermopower in the adiabatic condition, which is superposed on the isothermal transverse thermopower driven by the off-diagonal Seebeck effect. In this study, we calculate and observe the two-dimensional temperature distribution and the resultant transverse thermoelectric conversion in ATMLs comprising thermoelectric ${\mathrm{Co}}_2\mathrm{Mn}\mathrm{Ga}$ Heusler alloys and ${\mathrm{Bi}}_{2-a}{\mathrm{Sb}}_a{\mathrm{Te}}_3$ compounds. By our changing the tilt angle from 0° to 90°, the transverse temperature gradient obviously appeared in the middle angles and the transverse thermopower increases up to −121.9 µV/K in the ${\mathrm{Co}}_2\mathrm{Mn}\mathrm{Ga}/{\mathrm{Bi}}_{0.2}{\mathrm{Sb}}_{1.8}{\mathrm{Te}}_3$-based ATML at a tilt angle of 45° whereas the isothermal contribution is estimated to be −82.6 µV/K from the analytical calculation. This hybrid action derived from ODTC results in a significant increase of the maximum reduced conversion efficiency from 3.1% to 8.1% in calculations and from 2.3% to 4.4% in experiments.

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• Nernst effect
• Seebeck effect
• Thermal conductivity
• Thermoelectric effects
• Complex materials
• Multilayer thin films
• Semiconductor compounds
• Thermoelectric generators