In doped manganite systems, strong electronic correlations result in rich phase diagrams where electron delocalization strongly affects the magnetic order. Here, we employ a femtosecond all-optical pump-probe scheme to impulsively photodope the antiferromagnetic parent manganite system CaMnO₃ and unveil the formation dynamics of a long-range ferromagnetic state. We resonantly target intense charge transfer electronic transitions in CaMnO₃ to photodope the system and probe the subsequent dynamics of both charges and spins using a unique combination of time-resolved terahertz spectroscopy and time-resolved magneto-optical Faraday measurements. We demonstrate that photodoping promotes a long-lived population of delocalized electrons and induces a net magnetization, effectively promoting ferromagnetism resulting from light-induced carrier-mediated short-range double-exchange interactions. The picosecond set time of the magnetization, much longer than the electron timescale, and the presence of an excitation threshold are consistent with the formation of ferromagnetic patches in an antiferromagnetic background.

The development of “fault-tolerant” quantum computers, unaffected by noise and decoherence, is one of the fundamental challenges in quantum technology. One of the approaches currently followed is the realization of “topologically protected” qubits which make use of quantum systems characterized by a degenerate ground state of composite particles, known as “non-Abelian anyons”, able to encode and manipulate quantum information in a non-local manner. In this paper, we discuss the potential of quasi-two-dimensional electron gas (q2DEG) at the interface between band insulating oxides, like LaAlO3 and SrTiO3, as an innovative technological platform for the realization of topological quantum systems. Being characterized by a unique combination of unconventional spin-orbit coupling, magnetism, and 2D-superconductivity, these systems naturally possess most of the fundamental characteristics needed for the realization of a topological superconductor. These properties can be widely tuned by electric field effect acting on the orbital splitting and occupation of the non-degenerate 3dxy and 3dxz,yz bands. The topological state in oxide q2DEGs quasi-one-dimensional nanochannels could be therefore suitably controlled, leading to conceptual new methods for the realization of a topological quantum electronics based on the tuning of the orbital degrees of freedom.