Anisotropic quantum transport in EuTiO3

The quest for materials with high carrier mobility and controllable spin-polarizability continues to be one of the primary endeavors in the field of spintronics. Such materials have the potential to revolutionize many areas of energy and information technologies, enabling a quantum leap in processing and storing the data in electronic devices. The combination of high carrier mobility and spin-polarizability has, however, proven to be a challenging task. In practice, any form of magnetization tends to enhance the scattering rate of the charge carriers, thereby adversely affecting their mobility. we have recently demonstrated that EuTiO3 is a rare example of a magnetic semiconductor that can possess a high carrier mobility while exhibiting a strong magnetization whose direction can be desirably controlled via an external magnetic field. We have also found that this system can exhibit a high-degree of quantum coherence, manifesting as strong oscillations in magneto-resistance, also known as Shubnikov-de Haas (SdH) effect, with distinct directional anisotropy. Our first-principles calculations have further revealed that such a directional anisotropy in the SdH oscillations stems from a proximity-induced exchange coupling between Eu-4f moments and 3d carriers at the Fermi level. Altogether, our findings shed new light into quantum transport phenomena in magnetic materials offering a new paradigm for manipulating the spin, charge and orbital degrees of freedom of conducting electrons and their interplay with each other.