Title:	Interplay between spin and lattice degree-of-freedom in ultrafast dynamics
DNr:	NAISS 2024/5-625
Project Type:	NAISS Medium Compute
Principal Investigator:	Danny Thonig <danny.thonig@oru.se>
Affiliation:	Örebro universitet
Duration:	2024-12-01 – 2025-12-01
Classification:	10304
Homepage:	https://cahmd.gitlab.io/cahmdweb/
Keywords:

Abstract

In this proposal we will study from first-principles ultrafast dynamic in magnetic matrials when the magnetism strongly interacts with vibrations in the crystal strucure. Such dynamics is driven by a laser, external magnetic field or current pulses. Here, the present proposal focuses on the key question of the ultrafast magnetism experiments; how the angular momentum of the ferromagnetic state is transferred out of the spin system on fs- to ps time-scales, is so far unanswered. To address this, we will applying a classical description of combined spin-lattice dynamics simulations perturbed by an external ultrafast source (laser, magnetic field pulse, or current pulse). This task takles multipe topics in modern theory of magnetism, such as the question about exchange intetaction mechanisms or energy dissipation between spin and lattice, as well as the thermal conductivity properties, in particular at finite temperature. The planned project is naturally divided into several sub-projects, that involve studies of atomistic spin-lattice dynamics and electronic structure of correlated electron systems. All sub-projects will require a considerable computational effort. The different applications used in the projects are based on density functional theory, supplemented when necessary by many-body techniques such as dynamical mean field theory. We will be using the following electronic structure softwares: VASP [1], RSPt+DMFT [2], and HUTSEPOT[3], SPRKKR [4]. Applications based on the atomistic spin-lattice-dynamics simulation as well as Tight Binding tool implemented in Cahmd [5] will also be used in this project. These softwares perform very well on parallel architectures, as reported below. Major funding for personnel in this project are from: VR and KAW. [1] G. Kresse and J. Hafner. Phys. Rev. B, 47, 558 (1993). [2] J. M. Wills et al., Full-potential Electronic Structure Method; Energy and Force Calculations with Linear Muffin-Tin Orbitals (Springer, Vol. 167, 2010). [3] M. Hoffmann et al., Phys. Status Solidi B 257, 1900671 (2020); https://hutsepot.jku.at [4] H. Ebert, Fully relativistic band structure calculations for magnetic solids ed.: H. Dreyssé, Lec. Notes in Phys. 535, 191, Springer (1996); [5] https://cahmd.gitlab.io/cahmdweb/