superlattice

"Superlattice" is formed, for example, when a structural modulation occurs on a crystal structure to have a longer period (normally an integral multiple of the original period) than that of the original crystal structure. Such a modulation can be formed in a low-temperature phase due to phase transformation. An artificial superlattice is produced as a long-period multi-layer structure which is composed of more than two kinds of layer crystals deposited by molecular beam epitaxy (MBE). The superlattice structures are used for quantum-well laser diodes, high-temperature superconductive materials, and magnetic materials.