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The spin properties of molecules can be used for information storage.

The limitations of further miniaturisation of present-day electronic circuits are stimulating the search for new technologies to store and manipulate information.
The spin properties of molecules can be used for information storage.
Spintronics is one of the major new technologies to emerge in recent years. It aims to use the additional degree of freedom in small structures – their spin state – to store and process information.

Molecules and quantum dots are among the most promising candidates for future spintronic devices. In order to exploit such devices, it is crucial to fully understand their behaviour and properties. The transport properties of such nanostructures depend greatly on the quality of the contacts to external electrodes. When the coupling to the leads is relatively weak, Coulomb blockade and single-electron charging phenomena become relevant. If the coupling is strong and the temperature sufficiently low, the electronic correlations can give rise to the Kondo effect, which manifests itself as maximum conductance through the system.

The main objective of the SPINKOND (Spin effects in transport through magnetic nanostructures in the Kondo regime) project was to explore the transport characteristics of quantum dot and molecular structures coupled to external electrodes in the Kondo regime. The research involved hybrid nanostructures, such as quantum dots coupled to ferromagnetic and/or superconducting electrodes. Thermoelectric phenomena in spin-polarised transport through quantum dots and molecules were also investigated.

Depending on the ground state of the system and the particular device’s set-up, there can be different types of the Kondo effect. Within the SPINKOND project the so-called fully screened, under-screened and over-screened Kondo phenomena were all thoroughly investigated. The calculations were mainly performed with the aid of numerical renormalisation groups, which is a powerful numerical method to study transport through quantum impurity systems coupled to external leads.

The results obtained were published in 22 papers and presented at 13 conferences. They are expected to contribute to the general understanding of transport phenomena in various nanostructures exhibiting non-trivial correlations.

Project work is further expected to stimulate further theoretical and experimental research into the spin-polarised properties of quantum dots and molecules. SPINKOND developments will also be of assistance in explaining and understanding current and future experiments on transport through magnetic nanostructures.

Related information

Keywords

Spintronics, quantum dots, nanostructures, Kondo, SPINKOND
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