The concept of the spin gapless semiconductor in which both electron and hole can be fully spin polarized is proposed, and its possibility is presented on the basis of first-principles electronic structure calculations. Possible new physics and potential applications in spintronic devices based on the spin gapless semiconductors are discussed.

• Received 15 May 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.156404