For several years nanophysics was driven by the need for miniaturization of electronic circuits. It became obvious that this process has its physical limits, therefore novel concepts for electronic devices were developed, from which spintronics is one of the most succeful direction. In this novel concept the spin of the electron is used instead of its charge and the generation, manipulation and detection of spin currents are needed for building spintronics devices. This field got another boost with the discovery of 2D materials. Graphene has been established as great spin conductor, whereas other materials with large spin-orbit coupling allow the manipulation of spin currents by electrical means. 2D magnets, which have been recently discovered allow the generation and the detection of spin information. These ingredients can be built into van der Waals heterostructures allowing compact device architectures where all the functionalites are encoded in heterostuctures themselves.
The goal of the PhD project is to investigate spintronic heterostuctures which include 2D ferromagnets. These materials will be generated by mechanical exfoliation and will be combined using van der Waals stacking. The ferromagnetic materials will be characterized by transport measurements, e.g. anomalous Hall effect, or using resonance techniques, like ferromagnetic resonance. The ferromagnetic properties can also be engineered by coating these materials with a well-engineered molecular layers. These could change not only the critical temperature or the coercitivity the magnet, but also can induce novel functionalities, like tunability with optical stimuli. Moreover, in van der Waal structures the magnetization of 2D materials can also be switched using the spin torque effect. If the magnet is placed on a material with a large spin orbit interaction (SOC), than by passing a current through the SOC material a spin current can be generated, which can switch the ferromagnet.
During the PhD work the candidate will be involved in the fabrication of novel 2D heterostructures using 2D layer assembly and electron-beam lithography. The samples will be studied at low temperatures. The work is done in close collaboration with several European universities.
Left: Change of ferromagnetic properties via molecular doping. Right: van der Waals heterostructure with bilayer graphene sandwiched betwen Wse2 and Cr2Get2Te3.