Researchers worldwide are attempting to render quantum-physical effects usable for energy-saving and rapid information technology. Semiconductors might constitute the foundation therefor. The objective is to manipulate not only the optical and electrical properties of semiconductors, but also their magnetic properties. This can be achieved by controlling the spin of electrons in the semiconductor; through the direction of this intrinsic spin, information can be encoded in a system.
Quantum effects typically only occur on the atomic level. Under certain conditions, however, they can also have an impact on the macroscopic level, namely in case of a coherent overlap of multiple states. In a coherent system, the phases of different spin waves are interconnected in a certain way. However, due to external influences, the phases may shift and the coherence that gives meaning to the stored information may be disrupted.
The Collaborative Research Centre/Transregio 160 team is striving to manipulate not only individual coherent spins, but also interacting spins. In order to achieve this objective, high-purity semiconductors are necessary; the group is designing new material concepts for this purpose. Moreover, the collaboration partners are developing sophisticated theoretical models for spin interactions.
The interactions between the spins are tailor-cut, either to suppress harmful interactions with the environment and to maintain spin coherence, or in order to reinforce the interactions between the spins. Thus, the researchers have established overlaps and entanglements of quantum states, in order to achieve functionalities that cannot be realised in incoherent systems.