University of Twente Student Theses


Computational methods in quantum mechanics with applications in spintronic calculations

Rang, M.S. (2020) Computational methods in quantum mechanics with applications in spintronic calculations.

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Abstract:Energy consumption by and heat dissipation in central processing units (CPUs) are factors limiting the progress of computing technology. The heat produced by CPUs limits the further miniaturization, so even though one can fit billions of transistors on one chip, the total computational power is limited. If one could use the electron spin, rather than its charge, as the carrier of information, the heating problem would be suppressed, as spin currents do not suffer from the same energy dissipation (Joule heating) problem. Another great improvement would be that the energy consumption of the processor units would go down significantly. This is easier said than done. Electronics based on electron spin, or "spintronics" is a relatively young field, and our lack of knowledge still prohibits any extensive use of spintronics in devices. There are exceptions to this, most notably the giant magnetoresistance (GMR) effect, which is the operating principle of hard disk drives. There are still many unknowns with regard to spin currents in materials, which must be answered if spintronics is to be more widely implemented. This report focuses on a few spintronic properties of a particular material, namely platinum (Pt). Platinum has a large spin-orbit coupling, which is to say the orbital degrees of freedom couple strongly to the spin degrees of freedom, which in turn means that effects caused by electron spin are more noticeable. This, together with platinum (Pt) being a conductor, makes it a prime example in the study of spintronics. In order to do calculations, the Twente \MTO transport code" is used. Ways to expand and improve the code are also subject matter of this report, in fact, two thirds of the work is focused on these methods, in both a computational and mathematical sense. In the report, the formalisms used in the calculations are discussed first. Then, a few new results are derived, which were subsequently implemented in a computational code. The results section reports the values found through calculation, as well as some computational tests for the newly implemented methods. Finally, the conclusions and recommendations give a final overview of the project, and give recommendations for future research.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:31 mathematics, 33 physics, 51 materials science
Programme:Applied Mathematics MSc (60348)
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