Tunable charge and spin Seebeck effects in magnetic molecular junctions

2012/05/30 by Pablo S. Cornaglia, Gonzalo Usaj, C. A. Balseiro
Computer Science · Engineering · Physics and Astronomy · #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #Quantum-Dot Cellular Automata #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.86.041107

published as Phys. Rev. B 86, 041107(R) (2012) · 5 pages, 4 figures

arxiv created 2012/05/30 · openalex publication_date 2012/07/24 · arxiv updated 2012/07/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We study the charge and spin Seebeck effects in a spin-1 molecular junction as a function of temperature, applied magnetic field, and magnetic anisotropy (D) using Wilson's numerical renormalization group. A hard-axis magnetic anisotropy produces a large enhancement of the charge Seebeck coefficient S_c (\ensuremath∼k_B/|e|) whose value only depends on the residual interaction between quasiparticles in the low-temperature Fermi-liquid regime. In the underscreened spin-1 Kondo regime, the high sensitivity of the system to magnetic fields makes it possible to observe a sizable value for the spin Seebeck coefficient even for magnetic fields much smaller than the Kondo temperature. Similar effects can be obtained in C₆₀ junctions where the control parameter, instead of D, is the gap between a singlet and a triplet molecular state.

Citations

• The numerical renormalization group method for quantum impurity systems
• The renormalization group: Critical phenomena and the Kondo problem
• Singular dynamics of underscreened magnetic impurity models
• Mechanical Control of Spin States in Spin-1 Molecules and the Underscreened Kondo Effect
• A ?fermi-liquid? description of the Kondo problem at low temperatures