Quantum Transport Through a Stretched Spin--1 Molecule

TL;DR

This paper investigates electronic transport in a spin-1 molecule, revealing how magnetic anisotropy influences conductance and Kondo effects, aligning with recent experimental observations.

Contribution

It provides a theoretical analysis of how magnetic anisotropy affects Kondo phenomena and conductance in spin-1 molecules under various conditions.

Findings

Unstretched molecule reaches unitary conductance limit at low temperatures.

Magnetic anisotropy induces a second Kondo effect, reducing conductance.

Results explain experimental measurements of spin-1 molecules.

Abstract

We analyze the electronic transport through a model spin-1 molecule as a function of temperature, magnetic field and bias voltage. We consider the effect of magnetic anisotropy, which can be generated experimentally by stretching the molecule. In the experimentally relevant regime the conductance of the unstretched molecule reaches the unitary limit of the underscreened spin- 1 Kondo effect at low temperatures. The magnetic anisotropy generates an antiferromagnetic coupling between the remaining spin 1/2 and a singular density of quasiparticles, producing a second Kondo effect and a reduced conductance. The results explain recent measurements in spin-1 molecules [Science 328 1370 (2010)].