Transverse anisotropy effects on spin-resolved transport through large-spin molecules

TL;DR

This paper investigates how transverse magnetic anisotropy influences spin-dependent electron transport in large-spin molecules, revealing conditions under which the Kondo effect is restored and its impact on magnetoresistance.

Contribution

It provides a theoretical analysis of the interplay between transverse anisotropy and Kondo physics in large-spin molecules coupled to ferromagnetic leads, using numerical renormalization group methods.

Findings

Transverse anisotropy can restore the Kondo resonance suppressed by uniaxial anisotropy.

The Kondo peak restoration depends on magnetic configuration and affects tunnel magnetoresistance.

Temperature dependence of conductance at Kondo restoration points follows universal scaling.

Abstract

The transport properties of a large-spin molecule strongly coupled to ferromagnetic leads in the presence of transverse magnetic anisotropy are studied theoretically. The relevant spectral functions, linear-response conductance and the tunnel magnetoresistance are calculated by means of the numerical renormalization group method. We study the dependence of transport characteristics on orbital level position, uniaxial and transverse anisotropies, external magnetic field and temperature. It is shown that while uniaxial magnetic anisotropy leads to the suppression of the Kondo effect, finite transverse anisotropy can restore the Kondo resonance. The effect of Kondo peak restoration strongly depends on the magnetic configuration of the device and leads to nontrivial behavior of the tunnel magnetoresistance. We show that the temperature dependence of the conductance at points where the restoration of the Kondo effect occurs is universal and shows a scaling typical for usual spin-one-half Kondo effect.