Kramers doublet transition metal point defects in hexagonal silicon carbide

Transition metal (TM) point defects in silicon carbide (SiC) have attracted special attention recently owing to their highly promising properties with respect to quantum technology applications. Paramagnetic electronic structure of these defects exhibits a rich set of interesting and not yet fully resolved physics. A complex interplay between the electronic orbitals, phonons and electron spin determines the effective pseudospin of the system that we demonstrate on vanadium and molybdenum defects in hexagonal SiC by means of ab initio calculations [1]. Furthermore, we show that this interaction leads to the giant anisotropy in the g-tensor of the TM defects with Kramers doublet spin ground state, resulting in reduced and vanishing interaction with the magnetic field in parallel and transverse directions, respectively. The consequences of our finding in the application of these defects for quantum information processing will be discussed [1]. [1] A. Csóré, A. Gali, arXiv:1909.11587v2