Hole superconductivity in MgB2:: a high Tc cuprate without Cu

The theory of hole superconductivity explains high temperature superconductivity in cuprates as driven by pairing of hole carriers in oxygen p pi orbitals in the highly negatively charged Cu-O planes. The pairing mechanism is hole undressing and is Coulomb-interaction driven. We propose that the planes 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 similarly from undressing of hole carriers in the planar boron px,y orbitals in the negatively charged B- planes. Doping MgB2 with electrons and with holes should mirror the behavior of underdoped and overdoped high T-c cuprates, respectively. We discuss possible ways to achieve higher transition temperatures in boron compounds based on this theory. (C) 2001 Elsevier Science B.V. All rights reserved.