Developing silicon carbide for quantum spintronics

In current long-distance communications, classical information carried by large numbers of particles is intrinsically robust to some transmission losses but can, therefore, be eavesdropped without notice. On the other hand, quantum communications can provide provable privacy and could make use of entanglement swapping via quantum repeaters to mitigate transmission losses. To this end, considerable effort has been spent over the last few decades toward developing quantum repeaters that combine long-lived quantum memories with a source of indistinguishable single photons. Multiple candidate optical spin qubits in the solid state, including quantum dots, rare-earth ions, and color centers in diamond and silicon carbide (SiC), have been developed. In this perspective, we give a brief overview on recent advances in developing optically active spin qubits in SiC and discuss challenges in applications for quantum repeaters and possible solutions. In view of the development of different material platforms, the perspective of SiC spin qubits in scalable quantum networks is discussed. Funding Agencies|Swedish Research CouncilSwedish Research Council [VR 2016-04068, VR 2016-05362]; Swedish Energy AgencySwedish Energy Agency [43611-1]; EUEuropean Union (EU) [862721]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [KAW 2018.0071]; BMBF via Q.Link.XFederal Ministry of Education & Research (BMBF); AFOSRUnited States Department of DefenseAir Force Office of Scientific Research (AFOSR) [FA9550-15-1-0029, FA9550-19-1-0358]; DARPAUnited States Department of DefenseDefense Advanced Research Projects Agency (DARPA) [D18AC00015KK1932]; ONROffice of Naval Research [N00014-17-1-3026]; EUEuropean Union (EU)