Simulation of Spin Transport, Diffusion and Injection into Semiconductors
Lead Research Organisation:
University of York
Department Name: Physics
Abstract
Public demand for increasingly faster and smaller electronic devices, such as computers, requires that more and even smaller transistors are packed on every chip. This has led to the birth of nanotechnology and, more recently of the nanotechnology field called 'spintronics'. Here not only the charge, but also the spin -- another fundamental property of electrons and holes -- is used to design device functionalities. Among the potential benefits of spintronics devices is the possibility of computers in which the same unit is used for computation and storage, of lower power consumption, of miniaturisation, and more generally the possibility of designing conceptually new devices which mix old functionalities with completely new ones.The first commercial application of a spintronics-related effect was the read heads for magnetic hard disk drives by IBM in the 90s, which increased the storage on a disk drive to tens of gigabytes and have since then secured a market of billions of dollars. It is clear that every development in this fascinating field is important to the specialists as well as of the general public. The basis of spintronics is understanding the spin dynamics. Unfortunately key issues such as how to inject a current of spins in a semiconductor, how to sustain it across the interfaces of the different materials forming the devices, which materials/nanostructures are best and what lengths a current of spin can travel in a specific material are still open questions. This project aims to master the principles underlying the spin dynamics, with particular attention to applications such as nanocircuits and their components. My objectives are to fully understand spin transport, diffusion and injection into semiconductors. These properties are fundamental for developing semiconductor and hybrid (metal/semiconductor) spintronics devices. The problem of electrical spin injection into semiconductors (fundamental when thinking of an electronic circuit) is still open, as well as the understanding of the role played by many-body interactions in spin transport and dynamics. In this context the ability of performing computer simulations of these phenomena is of paramount importance. Simulations can in fact be thought as ideal experiments, which allow a systematic analysis of the system response even for conditions (e.g. extreme temperatures or defect-free or exotic materials) which are too difficult or expensive to reproduce in the lab. I plan to develop computer simulation codes using two powerful techniques, non-equilibrium Monte-Carlo and spin-dependent drift-diffusion equation techniques and apply them to spin-transport in bulk and through semiconductor heterostructures, to the study of many-body interaction effects, and, ultimately, to device components.In order to do so, I will need to develop and adapt the simulation techniques themselves to the specific problems as well as to develop the underlying spin-transport theory, for example in relation to many-body effects such as the spin Coulomb drag which I predicted in 2000 and was observed experimentally in 2005.In the second part of the project, I plan to combine non-equilibrium Monte-Carlo techniques with the atomistic model: the merger of these two techniques will allow me to analyse the effects of magnetic impurities and nanostructures with an accuracy never reached so far. My aims are to improve our understanding of spin-dynamics (especially many-body interaction effects), to solve the puzzle of electrical spin-injection into semiconductors and ultimately to design basic elements for spintronics circuitry components.
Organisations
People |
ORCID iD |
Irene D'Amico (Principal Investigator) |
Publications
Coe J
(2011)
Feasibility of approximating spatial and local entanglement in long-range interacting systems using the extended Hubbard model
in EPL (Europhysics Letters)
F. Baboux
(2013)
Anisotropic spin-orbit induced splitting of intersubband spin plasmons
in Eur. Phys. J. Web of Conferences 40, 18002 (2013)
Marchetti G
(2014)
Spin decoherence in n -type GaAs: The effectiveness of the third-body rejection method for electron-electron scattering
in Journal of Applied Physics
Chureemart P
(2015)
Model of spin accumulation and spin torque in spatially varying magnetisation structures: limitations of the micromagnetic approach.
in Journal of physics. Condensed matter : an Institute of Physics journal
Marchetti G
(2014)
Spin Relaxation in GaAs: Importance of Electron-Electron Interactions.
in Materials (Basel, Switzerland)
D'Amico I
(2010)
Coulomb interactions and spin transport in semiconductors: The spin Coulomb drag effect The spin Coulomb drag effect
in physica status solidi (b)
Coe J
(2010)
Hubbard model as an approximation to the entanglement in nanostructures
in Physical Review A
França V
(2011)
Entanglement from density measurements: Analytical density functional for the entanglement of strongly correlated fermions
in Physical Review A
Chureemart P
(2013)
Modeling spin injection across diffuse interfaces
in Physical Review B
D'Amico I
(2013)
Nonlocal formulation of spin Coulomb drag
in Physical Review B
Description | We developed a code which helps understanding the transport of spin in semiconductors. This is of help to the emerging technology called 'spintronics'. We have studied the transport of spins in metals and semiconductors towards the understanding of phenomena used in spintronics devices. We have studied basic phenomena related to spin dynamics in semiconductors and related low-dimensional structures |
Exploitation Route | Finding have been published in international journals where are accessible to the scientific community. The publications give the information necessary to others to carry the work forward. Results have been also presented to many conferences as invited talks, contributed talks and posters. |
Sectors | Digital/Communication/Information Technologies (including Software),Education,Electronics |
Description | Findings have been published on international journals including high impact publications and two invited articles. Similarly they have been presented to many international conferences as invited talks, contributed talks, and poster contributions. |
First Year Of Impact | 2010 |
Sector | Education |
Impact Types | Cultural |
Description | Funding for a PhD studentship and some travel as a York Team member in a European Union grant |
Amount | £60,000 (GBP) |
Funding ID | """FEMTOSPIN"", FP7-NMP-2011-SMALL-5 EU grant" |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 06/2012 |
End | 05/2015 |
Description | Royal Society of London |
Amount | £11,660 (GBP) |
Funding ID | IJP 2008/R1 JP0870232 |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 05/2009 |
End | 12/2011 |
Description | The Nuffield Foundation |
Amount | £1,440 (GBP) |
Funding ID | URB/39938 |
Organisation | Nuffield Foundation |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 07/2011 |
End | 08/2011 |