RESUMEN
FeSi is a nonmagnetic narrow-gap insulator, exhibiting peculiar charge and spin dynamics beyond a simple band structure picture. Those unusual features have been attracting renewed attention from topological aspects. Although the surface conduction was demonstrated according to size-dependent resistivity in bulk crystals, its topological characteristics and consequent electromagnetic responses remain elusive. Here, we demonstrate an inherent surface ferromagnetic-metal state of FeSi thin films and its strong spin-orbit coupling (SOC) properties through multiple characterizations of two-dimensional conductance, magnetization, and spintronic functionality. Terminated covalent bonding orbitals constitute the polar surface state with momentum-dependent spin textures due to Rashba-type spin splitting, as corroborated by unidirectional magnetoresistance measurements and first-principles calculations. As a consequence of the spin-momentum locking, nonequilibrium spin accumulation causes magnetization switching. These surface properties are closely related to the Zak phase of the bulk band topology. Our findings propose another route to explore noble metalfree materials for SOC-based spin manipulation.
RESUMEN
[9-(10-phenyl)anthryl](4-bromo-2,6-dimethylphenyl)diazomethane was found to be stable enough to survive Sonogashira coupling reaction conditions and was converted to [9-(10-phenyl)anthryl](4-trimethylsilylethynyl-2,6-dimethylphenyl)diazomethane, which was reacted with 1,8-diiodoanthracene to give bis(diazo) compound. Bis(carbene) generated by irradiation of the bis(diazo) compound generated a fairly persistent S = 2 quintet state. [structure: see text]