TUNEFIELD · First principles studies of the field-inducedtunability of dielectric properties
6РП — Действия „Мария Кюри“
- Период
- 2005-09-16 → 2008-09-15
- Финансиране от ЕС
- 251 595 €
- Участници
- 2
- Схема
- OIF
Линиите свързват координатора с партньорите.
Накратко на български
Спинтрониката изследва управлението на спина на електроните, например чрез пренасянето им от манганов оксид в въглеродна нанотръба. Това помага за предсказване на времето, през което информацията се запазва в наноустройствата, преди да бъде загубена.
Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.
Резултати накратко
Final Activity Report Summary - TUNEFIELD (First principles studies of the field-inducedtunability of dielectric properties)
Spintronic, or 'spin-electronic', is an emerging multidisciplinary field whose objective is the exploitation and manipulation of the intrinsic spin of electrons in solid-state devices. Two of the fundamental problems that need to be addressed in this field are the generation of a 'spin signal' and the lifetime of this signal in the device. Different approaches of spin generation exist, either by optical orientation of the spins or by direct injection from a ferromagnetic material. During this fellowship we proved spin-injection from a fully polarised manganese oxide (La0.7Sr0.3MnO3, or LSMO) into a Carbon nanotube (CNT). By performing first principles' simulations of the contact of the CNT with the LSMO, it was shown that the conducting electrons on the oxide were fully spin polarised, with only electrons with one well defined spin being conductive, and that an energy barrier existed between LSMO and CNT, two ingredients needed to understand the experimental observations. Once the spin was injected into a conductor, the spin information should be transmitted. However, during this transport of the spin information, a different scattering mechanism could flip the orientation of the spin. In metals, it was the scattering by lattice vibrations (phonons) that dominated. We worked on the implementation of new computational codes to calculate the coupling between electrons and phonons that gave rise to this relaxation of the spin information, using first principles. This would allow for the prediction of spin lifetime in nanodevices for spintronic applications.
Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз
Цел на проекта
The tunability of physical properties by application of an external electric field has created great excitation, mainly related to the development of new field effect transistors (FETs). The use of the field-effect approach to materials other than semiconductors brings many interesting opportunities in basic science and for the design of new electronic devices.This recent line of research is very appealing for electronic structure methods based in first principles, because a quantum mechanical description at the atomic level is required to understand the physical processes involved. The problem of a periodic crystal in a finite macroscopic electric field is a challenge from a fundamental point of view.The difficulties come from the unbounded nature of the quantum-mechanical position operator, and the fact that in a macroscopic field the electronic wave-functions are no longer of the Bloch form because the potential is non-periodic". Only recently have these fundamental problems been understood, and a few "abinitio" implementations of the algorithms required for studying electric fields in materials are now available for studying relatively simple systems (few atoms). This is enough for basic research, but not for the application of these methods to realistic nano-devices.Computer simulations of materials are a powerful scientific tool in physics, material science, surface science, chemistry, biology, or earth sciences. Nanotechnology will require simulations of systems with hundreds of atoms under the effect of electric fields. This research project proposes the implementation of tools to perform these calculations.Our main interest is the use of these tools for the study of the new electronic devices whose physical properties can be tuned by electric fields. The dielectric properties of SrTiO3/BaTiO3 superlattices, the electro-optical properties of semiconductor nanostructures and the electromechanical properties of nanotubes will be investigated."
Оригинален текст от CORDIS (на английски).
Участници
- CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS · MADRIDКоординаторИспания
- THE REGENTS OF THE UNIVERSITY OF CALIFORNIA · DAVIS, CALIFORNIAСъединени щати
Връзки
Данни: CORDIS, © Европейски съюз