Size Dependence of Kondo Scattering in Point Contacts

I. K. Yanson; V. V. Fisun; R. Hesper; A. V. Khotkevich; J. M. Krans; J. A. Mydosh; J. M. van Ruitenbeek

doi:10.1103/PhysRevLett.74.302

Size Dependence of Kondo Scattering in Point Contacts

I. K. Yanson, V. V. Fisun, R. Hesper, A. V. Khotkevich, J. M. Krans, J. A. Mydosh, and J. M. van Ruitenbeek

Phys. Rev. Lett. 74, 302 – Published 9 January 1995

Abstract

By utilizing a mechanically controllable break junction, point contact spectra $\frac{dV}{dI}$ were determined for various noble metals (Cu; Au) doped with magnetic impurities (Mn). The contact diameter $d$ could be varied continuously between ca. 2 and 50 nm. The zero bias maximum in $\frac{dV}{dI}$ due to the Kondo scattering exhibits a large broadening and increase of relative amplitude as $d$ is decreased. By using the theoretical expression for the logarithmic slope of $\frac{dV}{dI}$ vs $V$ we find a significant enhancement of exchange coupling parameter $J$ , which leads to an enormous increase in the apparent Kondo temperature $T_{K}$ for small contact diameters.

Received 26 April 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.302

Authors & Affiliations

I. K. Yanson^1,2, V. V. Fisun^1,2, R. Hesper¹, A. V. Khotkevich^1,2, J. M. Krans¹, J. A. Mydosh¹, and J. M. van Ruitenbeek¹

¹Kamerlingh Onnes Laboratorium, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands
²B. Verkin Institute for Low Temperature Physics and Engineering, 47, Lenin Avenue, 310164 Kharkov, Ukraine