An anonymous reader writes "A new technique allows allows 'thermocrystals' to be created that can manipulate heat (a vibration of the atomic lattice of a material). Predicted manipulations include the ability to selectively transmit, reflect or concentrate heat much like light waves can be manipulated by lenses and mirrors. 'Heat differs from sound, he explains, in the frequency of its vibrations: Sound waves consist of lower frequencies (up to the kilohertz range, or thousands of vibrations per second), while heat arises from higher frequencies (in the terahertz range, or trillions of vibrations per second).' Applications range from better thermoelectric devices to switchable heat insulating/transmitting materials (abstract). Perhaps this will result in better cooling/heating mechanisms or more efficient engines."