If one side of a conducting or semiconducting material is heated while the other remains cool, charge carriers move from the hot side to the cold side, generating an electrical voltage known as thermopower.

Past studies have shown that the thermopower produced in clean two-dimensional (2D) electron systems (i.e., materials with few impurities in which electrons can only move in 2D), is directly proportional to the entropy (i.e., the degree of randomness) per charge carrier.

The link between thermopower and entropy could be leveraged to probe exotic quantum phases of matter. One of these phases is the fractional quantum Hall (FQH) effect, which is known to arise when electrons in these materials are subject to a strong perpendicular magnetic field at very low temperatures.