Thermal rectification device

A thermal rectification device comprising:

• a first medium and a second medium, the first medium and the second medium being of the same material, and the first and second media being coupled via evanescent waves generated by surface phonon polaritons thermally excited on surfaces of the first and second media,
• a third medium provided on a surface of the first medium on a side toward the second medium;
• a gap formed between the second medium and the third medium for cutting off thermal conduction therebetween, heat transfer between the first and second media being performed mainly via the thermally excited evanescent waves, and the gap comprising a relative permittivity different from each relative permittivity of the second medium and the third medium;
• wherein heat flux which flows from the second medium to the first medium in a first state in which the second medium has a first temperature TH and the first medium has a second temperature TL lower than the first temperature TH differs in intensity from heat flux which flows from the first medium to the second medium in a second state in which the first medium has the first temperature TH and the second medium has the second temperature TL.