Kondo Effect in a Magnetic Field and the Magnetoresistivity of Kondo Alloys

Abstract

The effect of a magnetic field on the spectral density of a S = 1/2 Kondo impurity is investigated at zero and finite temperatures by using Wilson's numerical renormalization group method. A splitting of the total spectral density is found for fields larger than a critical value Hc(T = 0) ≈ 0.5TK , where TK is the Kondo scale. The splitting correlates with a peak in the magnetoresistivity of dilute magnetic alloys which we calculate and compare with the experiments on CexLa1−xAl2, x = 0.0063. The linear magnetoconductance of quantum dots exhibiting the Kondo effect is also calculated.

Kondo-Transport Spectroscopy of Single Molecule Magnets

“…The Kondo temperature is defined as the energy scale where the crossover to strong coupling takes place. We also calculated the spectral function within the T -matrix approach [18]:…”

Intrinsic and precipitate-induced quantum corrections to conductivity in La2/3Sr1/3MnOGao1, Cao2, Zhang3 et al. 2012Phys. Rev. B

“…[12][13][14][15] Extensive experimental and theoretical work has been performed, and several mechanisms have been discussed to interpret these resistivity minima. Amongst them are mechanisms based on spin-polarized tunnelling via grain boundaries, 16 Kondo-like effects ( magnetic-and charge-type), [17][18][19] and quantum interference effects (QIE) arising from electron-electron interactions and weak localization, 1,12 just to name a few. However, a clear picture has not yet emerged and is still under discussion 9,20 impeding our understanding of the physics of correlated electron systems.…”

Kondo spin splitting with slave boson

“…The splitting was initially predicted [7] to be ±gµ B B around the Fermi level, in line with [2]. However, more recent calculations [8] shows that the splitting will be observable only above B c , when ∆ B becomes competitive with the Kondo temperature k B T K (k B : Boltzmann constant), which defines the strength of the spin screening. In addition, Moore and Wen [9] were successful in establishing the relationship between the field induced spin splitting in the spectral function of the system in equilibrium and the splitting that appear in the differential conductance when the system is slightly out of equilibrium.…”