Hole superconductivity in MgB2: a high T-c cuprate without Cu

The theory of hole superconductivity explains high temperature superconduct ivity in cuprates as driven by pairing of hole carriers in oxygen p pi orbi tals in the highly negatively charged Cu-O planes. The pairing mechanism is hole undressing and is Coulomb-interaction driven. We propose that the pla nes of B atoms in MgB2 are akin to the Cu-O planes without Cu, and that the recently observed high temperature superconductivity in MgB2 arises simila rly from undressing of hole carriers in the planar boron px,y orbitals in t he negatively charged B- planes. Doping MgB2 with electrons and with holes should mirror the behavior of underdoped and overdoped high T-c cuprates, r espectively. We discuss possible ways to achieve higher transition temperat ures in boron compounds based on this theory. (C) 2001 Elsevier Science B.V . All rights reserved.