Year: 2001
Type: article
Abstract: A series of calculations on ${\mathrm{MgB}}_{2}$ and related isoelectronic systems indicates that the layer of ${\mathrm{Mg}}^{2+}$ ions lowers the nonbonding B $\ensuremath{\pi}$ ( ${p}_{z}$) bands relative to the bonding $\ensuremath{\sigma}$ ( ${\mathrm{sp}}_{x}{p}_{y}$) bands compared to graphite, causing $\ensuremath{\sigma}\ensuremath{\rightarrow}\ensuremath{\pi}$ charge transfer and $\ensuremath{\sigma}$ band doping of 0.13 holes/cell. Because of their two dimensionality the $\ensuremath{\sigma}$ bands contribute strongly to the Fermi level density of states. Calculated deformation potentials of $\ensuremath{\Gamma}$ point phonons identify the B bond stretching modes as dominating the electron-phonon coupling. Superconductivity driven by $\ensuremath{\sigma}$ band holes is consistent with the report of destruction of superconductivity by doping with Al.
Source: Physical Review Letters
Authors: J. M. An, W. E. Pickett
Institution: University of California, Davis
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2001279659