  We propose a thermoelectric device that can produce a thermal gradient even
in a uniform-temperature environment. We introduced a metamaterial absorber
(MA), which comprised a transparent calcium fluoride layer sandwiched between a
silver mirror layer and silver microdisk arrays, at one end of a thermoelectric
device made of bismuth antimony telluride. The heating efficiencies of the MA
and opposite electrodes of the device were unbalanced; consequently, the
Seebeck effect was induced, resulting in electricity generation. We fabricated
the MA on a copper electrode loaded on a thermoelectric device, and the device
was placed in a uniform-temperature environment at 364 K. The thermal gradient
across the device was experimentally measured and was found to be 0.14 K.
