Tight-binding electronic structure calculations for the TiFe(001) surface

摘要

We present a self-consistent tight-binding calculation of the electronic structure for the (001) surface of TiFe in the CsCl (B2) structure. The results were obtained using a three-center s-p-d orthogonal tight-binding Hamiltonian, within the surface Green function matching formalism. We have analyzed the local density of states (LDOS) for cases where Fe or Ti forms the surface layer. When Fe forms the atomic surface layer, our calculations show that the corresponding LDOS consists predominantly of bonding states, like in the bulk, but with a value at the E-F enhanced by similar to 160 with respect to the bulk. When Ti forms the atomic surface layer, the corresponding LDOS consists mainly of antibonding states, but with a value at E-F raised compared with the bulk by similar to 350; a strong d-band narrowing was found in this case. Additionally, the trends to surface segregation and chemical activity for these surfaces are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. References: 33