Large Spin Splitting and Interfacial States in a Bi/BaTiO3(001) Rashba Ferroelectric Heterostructure

As an avenue to spintronics, controlling spin-polarized electronic states in low-dimensional heterostructures is at the frontier of physics and nanotechnology. Manipulating these states via ferroelectric polarization seems promising, but actually making high-quality interfaces, to realize states with large spin splitting upon a ferroelectric substrate, remains tricky. The authors rise to the challenge, directly demonstrating metallic states with large spin splitting in the wide band gap of BaTiO${}_{3}$, with evidence for considerable coupling between overlayer and substrate.