Tuning MgB_2(0001) surface states
arXiv:1105.2593 · doi:10.1103/PhysRevB.84.104514
Abstract
Surface state localization and hybridization on B, Mg, and Li terminated MgB_2(0001) surfaces are studied within density functional theory (DFT). For the B terminated surface we find a low energy B σ_1 surface state, a spz surface state, and B σ_2 and σ_3 quantum well states, which are 90% localized in the topmost B layer. Our results demonstrate that by charging the B atomic layer, either by changing the surface termination or through electro-chemical doping, the B σ surface states are shifted down in energy, filled, and delocalize through hybridization as they cross the bulk MgB_2 bulk bands. On the other hand, the spz surface state should be shifted up in energy, emptied, and gain an increasingly metallic s character by adding a Mg, Mg^{+1}, or Li terminating atomic layer. These results clearly show both the robust nature of MgB_2(0001) surface states, and how their localization and energy range may be tuned by surface termination and charging, with implications for the superconducting and plasmonic behaviour of MgB_2.
11 pages, 11 figures, 4 tables
References in corpus (6)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Plasmon-phonon coupling in graphene
- Plasmon-phonon Strongly-Coupled Mode in Epitaxial Graphene
- Trends in Metal Oxide Stability for Nanorods, Nanotubes, and Surfaces
- Low-Energy Charge-Density Excitations in MgB: Striking Interplay between Single-Particle and Collective Behavior for Large Momenta
- Ultrathin MgB2 films fabricated on Al2O3 substrate by hybrid physical-chemical vapor deposition with high Tc and Jc