Quantum Transport Through a Stretched Spin--1 Molecule

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)].

5 pages, 3 figures, minor changes, accepted for publication in EPL

References in corpus (8)

• The numerical renormalization group method for quantum impurity systems
• Mechanical Control of Spin States in Spin-1 Molecules and the Underscreened Kondo Effect
• Quantum phase transition in a single-molecule quantum dot
• Strongly correlated regimes in a double quantum-dot device
• Properties of anisotropic magnetic impurities on surfaces
• Correlated electron physics in multilevel quantum dots: phase transitions, transport, and experiment
• Singlet-triplet transition in a lateral quantum dot
• Conductance of a spin-1 quantum dot: the two-stage Kondo effect