Computational design of spin-caloric nanosructures

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Modern information technology is based to a great extent on nanometer-sized magnetic systems. Information is stored in magnetic nanostructures that reside on hard disks or in magnetic memories. This information is read-out, and in many cases written-in, by spin-polarized currents, i.e., electrical currents carrying a magnetization. These currents inevitably contribute to heat production and heat transport, summarized with the term “caloric effects.” The inverse phenomenon, i.e. the creation of a spin-polarized electron current due to a heat current that is forced by a temperature gradient, is inevitable as well. We therefore face a coupling between the charge, spin, and heat current in these systems. Such phenomena depend strongly on the type of material, but they also depend on the nanostructure size and geometry because of an effect known as quantum confinement. This is basically caused by the reflection of electrons at the nanostructure boundaries and crucially affects the density of quantum levels of the system. Here we propose a theoretical and computational study of the coupling of charge, spin and heat currents in nanostructured systems, analyzing and possibly optimizing the influence of material type and structure parameters. The study will take place with state-of-the-art quantummechanical methods. We anticipate that at the end of the funding period we will understand how to tune the spin-caloric transport properties of nanostructures to values that are desired for application.