Electronic theory of ultrafast spin dynamics

磁性介质的存储密度和读写速度的巨大增长正在达到其物理极限。实际的读写过程以纳秒为单位进行。新开发的方法，如进动开关，已经显示出达到100皮秒时间尺度的潜力，而竞争的非磁性光学技术已经证明了更快的开关。因此，需要加快磁动力学是迫在眉睫的。因此，从理论上探索和理解亚皮秒时间尺度下自旋动力学的物理过程、可能性和局限性是本项目的目标。该项目将侧重于磁开关全光技术的理论探索，该技术保证了器件的无接触操作模式，利用了超快时间尺度上磁动力学的相对论性和量子性。铁磁性金属、反铁磁性过渡金属氧化物和小磁性纳米颗粒将作为本理论研究的原型材料。这些材料的量子力学描述的电子理论将基于第一性原理和参数化方法，以便能够同时解释材料科学和超快自旋动力学的磁光方面。

The tremendous increase in storage density and read/write speed in magnetic media is reaching its physical limits. Actual read-write processes take place in the order of nanoseconds. Newly developed methods, like precessional switching, have shown the potential to reach time scales of a hundred picoseconds, while competing non-magnetic optical technologies have already demonstrated even faster switching. Therefore, the need for an upspeed of magnetic dynamics is imminent. Thus it is the goal of this project to theoretically explore and understand the physical processes, possibilities, and limitations of spin dynamics on the subpicosecond time scale. The project will be focussed on the theoretical exploration of all-optical technologies of magnetic switching, which guarantee a contact-free mode of device operation, exploiting the relativistic and quantum nature of magnetic dynamics on ultrafast time scales. Ferromagnetic metals, antiferromagnetic transition metal oxides, and small magnetic nanoparticles will be taken as prototypical materials for this theoretical investigation. The electronic theory for the quantum mechanical description of these materials will be based on both first principles and parametrized approaches in order to be able to account for the materials science and the magneto-optical aspects of ultrafast spin dynamics simultaneously.