Quantum spintronics in novel two-dimensional magnets

NAISS 2023/5-238


NAISS Medium Compute

Principal Investigator:

Biplab Sanyal


Uppsala universitet

Start Date:


End Date:


Primary Classification:

10304: Condensed Matter Physics

Secondary Classification:

10407: Theoretical Chemistry



The recent development in the field of two-dimensional (2D) magnets has created a lot of attention as these are potential candidates for ultra thin spintronic devices. These 2D magnets and their van der Waals (vdW) bonded heterostructures are extremely interesting due to enormous possibilities of manipulating their magnetic properties by strain, electric gating, proximity effects etc. Although a lot of works have been devoted to understand their electronic and magnetic properties, spin transport through these vdW systems has not been explored so much. This is important as one needs to evaluate the efficiency of spin transport and spin manipulation for the development of future devices at room temperature and above. The goal of this proposal is to theoretically and numerically study the quantum transport properties of novel 2D magnetic materials, which show a long range magnetic order at high temperatures. However, the calculations of magnetoresistance of huge systems with thousands of atoms by ab initio quantum transport theory in a controllable way is quite challenging. In this project, first, we will study the stability of the materials using force optimisation of geometries and phonon calculations. Then the electronic and magnetic properties will be calculated. Next, the transport calculations for the electrodes and devices with many numbers of atoms will be done. All these calculations will be performed using QuantumATK package. 2D metallic magnets such as Fe_nGeTe_2 (n=3,4,5) will be considered. These magnets exhibit high magnetic ordering temperatures. We will perform systematic studies of layer and stacking dependence on the transport properties. We will explore the effects of electron correlation, spin-orbit coupling and external fields. Moreover, magnetoresistance and quantum transport properties in the presence of external disorder, magnetic field and laser irradiation will be calculated with tight-binding Hamiltonian generated from density functional theory calculations and Wannierization of Kohn-Sham orbitals. This part will be done by Quantum Espresso code. We have already published a number of papers on 2D magnets. Therefore, our vast experience in this research field will be extremely beneficial for the successful outcome of the project.