Porozumění vrstevnatým magnetickým systémům pomocí výpočetních metod
| Thesis title in Czech: | Porozumění vrstevnatým magnetickým systémům pomocí výpočetních metod |
|---|---|
| Thesis title in English: | Computational understanding of layered magnetic systems |
| Key words: | magnetizační dynamika|numerické simulace|nízkodimenzionální systémy|spinové modely|nanomateriály |
| English key words: | magnetization dynamics|numerical simulations|low dimensional systems|spin models|nanomaterials |
| Academic year of topic announcement: | 2021/2022 |
| Thesis type: | dissertation |
| Thesis language: | čeština |
| Department: | Department of Condensed Matter Physics (32-KFKL) |
| Supervisor: | doc. RNDr. Karel Carva, Ph.D. |
| Author: | hidden - assigned and confirmed by the Study Dept. |
| Date of registration: | 01.09.2021 |
| Date of assignment: | 01.09.2021 |
| Confirmed by Study dept. on: | 01.10.2021 |
| Guidelines |
| Jedná se o teoretickou práci s využitím znalostí kvantové mechaniky a statistické fyziky, především principů magnetických interakcí a magnetického uspořádání. Uchazeč analyzuje existující modely popisující podobné problémy a ověří jejich aplikovatelnost na zadanou situaci. Předpokládá se numerické řešení stochastických problémů, především metodou Monte Carlo a tzv. magnetizační dynamikou, a spolupráce na získávání vstupních parametrů pro tyto simulace pomocí ab initio výpočetních metod. Bude třeba zpracovat velké objemy získaných dat, vyvodit z nich obecné závěry, a také kvalitně interpretovat experimentální data. Blíže bude upřesněno ve studijním plánu doktoranda.
EN: This represents theoretical work based on quantum mechanics and statistical physics, in particular principles of magnetic interaction and magnetic ordering. The applicant should analyse existing models describing similar problems and verify its applicability to the studied systems. He is expected to solve numerically stochastic problems, foremost using the Monte Carlo method and magnetization dynamics method, and to collaborate on obtaining input parameters for these simulations using ab initio computational methods. During the research he will need to process large amounts of data, understand them, draw possible conclusions, and also interpret comparable experimental findings. More details will be given in the individual study plan. |
| References |
| N. Majlis, The Quantum Theory of Magnetism (World Scientific Publishing, Singapore, 2000)
O. Eriksson, A. Bergman, L. Bergqvist, and J. Hellsvik, Atomistic Spin Dynamics: Foundations and Applications (Oxford University Press, Oxford, 2017). B. Huang, et al., Nature 546, 270−273 (2017) M. Gibertini, et al., Nature Nanotech. 14, 408 (2019) J. L. Lado and J. F. Rossier, 2D Mater. 4, 035002 (2017). |
| Preliminary scope of work in English |
| Atomically thin materials have the potential to revolutionize technologies from nanoelectronics to optoelectronics and from catalysis to coatings. The ability to control the electronic states of two-dimensional (2D) materials is expected to lead to new physical phenomena and device concepts. Graphene is one of the most interesting 2D materials because of its unique band structure leading to electrons behaving like massless particles. There is a large number of materials composed of layers coupled by weak van der Waals forces, which allow for easy layer separation and arbitrary stacking of these.
Even more recently, 2D materials with magnetism have been discovered. These specific materials can be well described by either Heisenberg or Ising Hamiltonian with an additional complicated anisotropic contribution. It is desirable to examine the consequences of various anisotropy terms. Due to their intrinsic magnetocrystalline anisotropy, several vdW magnets could be thinned down to nanoscale thickness, while still maintaining magnetism. Deeper understanding of the measured results will be possible due to ab initio calculations. Especially the unusual behaviour of the magnetocrystalline anisotropy needs an interpretation that could stem from examining contributions of individual 3d orbitals and their energies. Calculations can also reveal how the pressure modifies this energetics, as well as exchange interactions responsible for magnetic order. Calculations can help interpret possible unusual transport properties due to their ability to selectively enable/disable effects that influence transport, as is the spin-orbit interaction, magnetic disorder or phonon induced displacements. |