Revealing the spin and symmetry properties of the buried Co2MnSi/MgO interface by low energy spin-resolved photoemission

摘要

We present a novel approach to study the spin and symmetry electronicproperties of buried interfaces using low-energy spin-resolved photoemissionspectroscopy. We show that this method is sensitive to interfaces buried belowmore than 20ML (~4nm) MgO, providing a powerful tool for the non-destructivecharacterization of spintronics interfaces. As a demonstration, we apply thistechnique to characterize the Co2MnSi/MgO interface, a fundamental buildingblock of state-of-the-art magnetic tunnel junctions based on Heusler compounds.We find that a surface state with {\Delta}1 symmetry and minority spincharacter dominating the electronic structure of the bare Co2MnSi(100) surfaceis quenched at the Co2MnSi(100)/MgO interface. As a result, the interfacespin-dependent electronic structure resembles the theoretically expectedCo2MnSi bulk band structure, with majority spin electronic states of both{\Delta}1 and {\Delta}5 symmetry. Furthermore we find an additionalthermally-induced contribution in the minority channel, mirroring the{\Delta}1/{\Delta}5 asymmetry of the majority channel.