The objective of this proposal to study the rich quantum phenomenology associated with nanostructures of novel quantum materials. Focus of the study is on magnetism in 2D van der Waals materials and 3D quantum materials such as topological insulators (TI) and topological semimetals realized in thin films, thin film-heterostructures and nanowires. We also intend to initiate a new study based on the use of Big Data and machine learning algorithms to characterize the topological phases of these systems. Specific goals for the coming year (March 2022 - December 2022) are: 1) To probe valley-polarization effects and quantum transport in van der Waals heterostructures consisting of 2D materials and magnetic substrates. 2) Prediction of new antiferromagnetic materials, theoretical characterization of fundamental magnetic parameters, and their potential usage in antiferromagnetic spintronics. 3) to model spin-dependent transport in quasi 1D NWs and core-shell NW heterostructures of different classes of topological insulators, topological crystalline insulators and Weyl topological semimetals. This project is supported by the Carl Trygger Stiftelse grant for the period 2021-2023 and involves considerable code development and massive computational work. 4) to study spin-dependent transport in magnetic material/topological insulator heterostructures, magnetic material/Weyl semimetal heterostructures and magnetic material/Dirac semimetal heterostructure using first-principles method. In particular, we will investigate how the magnetization at the interface can be controlled through the spin-orbit torque and spin-transfer torque. These first four projects will provide crucial theoretical support to a parallel experimental activity being developed at LNU and based on the use of molecular beam epitaxy (MBE) techniques. This collaboration is partly supported by two VR grants: grant 2017-04404, with PI Janusz Sadowski and C.M. Canali and F. Islam as co-investigators; VR grant 2021-04622, with PI C.M. Canali. This work is also part of the activity of the Knowledge Environment (Kunskapsmiljö) “Advanced Materials” recently established at LNU. https://lnu.se/en/meet-linnaeus-university/knowledge-environments/advanced-materials/ 5) Big Data and machine learning techniques are acquiring an increasingly prominent role in condensed matter physics. We intend to initiate exploratory work aimed at using these computational techniques in the characterization of the topological phases of these quantum materials. For this purpose, we will benefit from the technical (computer science) expertise of the Linnaeus University Research center DISA https://lnu.se/forskning/sok-forskning/linnaeus-university-centre-for-data-intensive-sciences-and-applications/ with which we will establish ties.

 Other ongoing projects that will continue in 2022: 6) Continuation of the study on quantum anomalous Hall and axion insulator phases in magnetic thin films and TI heterostructures. 7) Theoretical investigation of multiferroic properties of chiral molecular magnets for the realization of controllable molecular qbits. We plan to continue this project by considering other molecules in this class, where the spin-electric coupling is accompanied by a ferroelectric effect, which makes these molecules an example of multiferroic molecular magnetic qubits. A second goal of the project is the theoretical study on how the spin-electric coupling is affected by attaching these molecules to metallic leads in molecular junctions, or by positioning them on surfaces, so that they can be addressed in quantum transport experiments.