Mechanical Control of Spin States in Spin-1 Molecules and the Underscreened Kondo Effect
The ability to make electrical contact to single molecules creates opportunities to examine fundamental processes governing electron flow on the smallest possible length scales. We report experiments in which we controllably stretched individual cobalt complexes having spin S = 1, while simultaneously measuring current flow through the molecule. The molecule's spin states and magnetic anisotropy were manipulated in the absence of a magnetic field by modification of the molecular symmetry. This control enabled quantitative studies of the underscreened Kondo effect, in which conduction electrons only partially compensate the molecular spin. Our findings demonstrate a mechanism of spin control in single-molecule devices and establish that they can serve as model systems for making precision tests of correlated-electron theories.
Copyright 2016 by the American Association for the Advancement of Science; all rights reserved. 11 January 2010; accepted 29 April 2010 We thank I. Cohen, M. Grobis, G. Hutchison, and P. McEuen for discussions and K. Bolotin, J. Grose, F. Kuemmeth, and E. Tam for technical help. Research at Cornell was supported by the NSF through the Cornell Center for Materials Research, DMR-0605742, CHE-0403806, and use of the Cornell Nanofabrication Facility/National Nanotechnology Infrastructure Network. T.A.C. acknowledges supercomputer support by the John von Neumann Institute for Computing (Jülich). P.S.C., A.A.A., and C.A.B. were supported by Proyectos de Investigación Plurianuales 11220080101821 of CONICET.
Supplemental Material - 07/328.5984.1370.DC1/Parks.SOM.pdf
Accepted Version - 1005.0621.pdf