Title:	Transport phenomena and nano-magnetic properties from first principles for engineering applications
DNr:	SNIC 2015/16-17
Project Type:	SNIC Large Compute
Principal Investigator:	Anna Delin <annadel@kth.se>
Affiliation:	Kungliga Tekniska högskolan
Duration:	2016-01-01 – 2017-01-01
Classification:	10304 10407
Homepage:	http://www.kth.se/en/ict/forskning/material-och-nanofysik
Keywords:

Abstract

The overarching theme of the ongoing and planned research in the group is to investigate transport properties and their relation to spin motion and magnetic properties, using first-principles computational methods and its build-ons, such as atomistic spin dynamics. We also construct and use models based on the discrete nonlinear Schrödinger equation. "Transport" is here used in a general sense and includes primarily transport of heat, electricity, polarons and magnons. A very intriguing prospect is to generalize the thermoelectric concept to spin voltages and spin currents. This leads to spin caloritronics. We will continue this work, using spin dynamics simulation tools, and investigate how to spincaloritronic devices. We are investigating graphene systems for electronic and photonic applications together with the experimental groups of Östling and Lemme (KTH and University of Siegen). An important aim is to understand how the transport properties of graphene may be altered by molecules attaching to the graphene surface. We have also initiated studies of altternative 2D materials and contact resistance in graphene systems. Further, we are investigating the thermoelectric properties of conducting polymers, specifically PEDOT chains. The work is in collaboration with the Crispin group in Linköping, who recently demonstrated polymer-based thermoelectricity. We also model amorphous alloys using the recently developed stochastic quenching method, making it possible to calculate the magnetic properties of these highly complex materials from first principles. Only recently, HPC resources have become powerful enough to allow advanced calculations, founded in quantum mechanics, of transport properties such as thermoelectric effects, magnonics and conductivity in systems where disorder play an important role. Recent method development has also helped to make this subject come into focus for computations. The VASP, SIESTA/SMEAGOL, CPMD, and Quantum Espresso calculations are envisaged to run on Triolith, Beskow and Abisko, whereas the UppASD calculations will be, for the most part, performed on Beskow. In the latter calculations, the number of atoms in a calculation can be counted in billions, and the code runs efficiently on over 10 000 cores in parallel. Our average total usage during the period Jan 1, 2015-Oct 10, 2015 was 917 kcore hours per month, which corresponds to 141% of our approved allocation and 96% of the allocation we requested last year. The machine we use the most is by far Beskow.