Computer simulations suggest that creating hot and cold regions
within a specific arrangement of semiconductors generates
internal electric currents and magnetic fields. If borne out by
experiments, the new effect, reported 8 July in Physical Review
B, could lead to improvements in electronic devices that heat up
in use. Experts are intrigued by the effect but remain cautious
about its practical importance until they see experimental data.
Temperature differences, or “gradients,” can have important
effects on the flow of current in a semiconductor because the
electrons or holes tend to drift from hotter regions toward
colder ones. Such thermal effects can also interact with
electric and magnetic fields, as in the so-called
thermoelectromagnetic effects. For instance, in the Nernst
effect, when a semiconductor is exposed to a temperature
gradient and a magnetic field at right angles to each other, a
small electric field is produced in the third direction.
Semiconductors in electronic devices often develop temp