PubMed Health⌕ Search

Biomedical subjects

Herbert Schoeller

Publications and source records attributed to Herbert Schoeller.

3 recordsLinked to original sources

Fingerprints of the magnetic polaron in nonequilibrium electron transport through a quantum wire coupled to a ferromagnetic spin chain.

We study nonequilibrium quantum transport through a mesoscopic wire coupled via local exchange to a ferromagnetic spin chain. Using the Keldysh formalism in the self-consistent Born approximation, we identify fingerprints of the magnetic polaron state formed by hybridization of electronic and magnon states. Because of its low decoherence rate, we find coherent transport signals. Both elastic and inelastic peaks of the differential conductance are discussed as a function of external magnetic fields, the polarization of the leads, and the electronic level spacing of the wire.

Journal Article↗

Nonlinear transport through a nanoscale molecule.

A simple model of electrical transport through a metal-aromatic molecule-metal system that includes charging effects as well as aspects of the electronic structure of the molecule, is presented. The interplay of a large charging energy and an asymmetry of the metal-molecule coupling can lead to various effects in nonlinear electrical transport. In particular, strong negative differential conductance is observed under certain conditions.

Electrons↗

Quantum phase transition in a multilevel dot.

We discuss electronic transport through a lateral quantum dot close to the singlet-triplet degeneracy in the case of a single conduction channel per lead. By applying the numerical renormalization group, we obtain rigorous results for the linear conductance and the density of states. A new quantum phase transition of the Kosterlitz-Thouless-type is found, with an exponentially small energy scale T(*) close to the degeneracy point. Below T(*), the conductance is strongly suppressed, corresponding to a universal dip in the density of states. This explains recent transport measurements.

Journal Article↗