  The thermopower in a two-dimensional semimetal existing in HgTe quantum wells
18-21 nm thick has been studied experimentally and theoretically for the first
time. It has been found theoretically and experimentally that the thermopower
has two components - diffusion and phonon drag and that the second component is
several times larger than the first. It has been concluded that the
electron-hole scattering plays an important role in both mechanisms of the
thermopower.
