Bias-voltage dependence of the magneto-resistance in ballistic vacuum tunneling: Theory and application to planar Co(0001) junctions

摘要

Motivated by first-principles results for jellium and by surface-barriershapes that are typically used in electron spectroscopies, the bias voltage inballistic vacuum tunneling is treated in a heuristic manner. The presentedapproach leads in particular to a parameterization of the tunnel-barrier shape,while retaining a first-principles description of the electrodes. The proposedtunnel barriers are applied to Co(0001) planar tunnel junctions. Besidesdiscussing main aspects of the present scheme, we focus in particular on theabsence of the zero-bias anomaly in vacuum tunneling.