While electron doping in incipient ferroelectrics like ${\mathrm{SrTiO}}_3$ and ${\mathrm{KTaO}}_3$, via chemical substitution or heterostructure engineering, has revealed a wealth of collective quantum phenomena, its effect in ${\mathrm{CaTiO}}_3$ remains largely unexplored. In this work, we investigate the change in electronic properties of ${\mathrm{CaTiO}}_3$ single crystal via the introduction of oxygen vacancy. Our magnetotransport measurements reveal clear signatures of Kondo scattering, arising from the interaction between conduction electrons and localized magnetic moments. Employing hard x-ray photoemission spectroscopy combined with DFT calculations, we unravel the underlying electronic structure and demonstrate the dichotomic nature of oxygen vacancy induced electron doping: a fraction of vacancy-donated electrons occupy states near the Fermi level, driving metallic behavior, while the remainder localize in deep in-gap states, acting as magnetic moments responsible for Kondo scattering. Owing to the polar nature of ferroelastic domain walls in pristine ${\mathrm{CaTiO}}_3$ [Phys. Rev. Lett. 101, 097602 (2008)], electron-doped ${\mathrm{CaTiO}}_3$ offers a compelling platform to investigate the intricate interplay between localized magnetic moments and electric dipoles embedded within a Fermi sea. Furthermore, controlled manipulation of domain wall polarity may unlock novel functionalities, offering promising avenues for next-generation electronic devices.

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• Dielectric properties
• Doping effects
• Kondo effect
• Magnetotransport
• Vacancies
• Ferroelectrics
• Single crystal materials
• Density functional calculations
• Hard x-ray photoelectron spectroscopy