Ultrafast separation of photodoped carriers in mott antiferromagnets

Abstract

We use inhomogeneous nonequilibrium dynamical mean-field theory to investigate the spreading of photoexcited carriers in Mott insulating heterostructures with strong internal fields. Antiferromagnetic correlations are found to affect the carrier dynamics in a crucial manner: An antiferromagnetic spin background can absorb energy from photoexcited carriers on an ultrafast time scale, thus enabling fast transport between different layers and the separation of electron and holelike carriers, whereas in the paramagnetic state, carriers become localized in strong fields. This interplay between charge and spin degrees of freedom can be exploited to control the functionality of devices based on Mott insulating heterostructures with polar layers, e.g., for photovoltaic applications. © 2014 American Physical Society.