Teilprojekt 4
TP4
Control of nonlinear self-localization phenomena of strongly coupled charge carriers in LiNb1-xTaxO3(LNT) solid solutions
The subproject sheds light on the cross-scale interaction of incoherent transport phenomena of strongly coupled charge carriers with the
- intrinsic defect structure of the solid solution system at the atomic level including the electronic structure,
- extended defect structures and their dielectric, mechanical and electronic properties, in particular with domain walls, interfaces & mechanical strain in thin film systems and
- compensating coherent transport properties and ionic diffusion.
The question of the microscopic origin of fs-pulse-induced, polaronic-based, long-lived volume photovoltaic net current densities in polar oxide solid-state material systems and their control via the targeted interaction of intrinsic and extended defect structures is being investigated. Based on the findings of the first funding phase, LNT represents an excellent model system for this purpose, as it exhibits novel polaronic (mixed) states in a previously unknown, multi-component defect landscape, enables the control of the self-localization of charge carriers, in particular the associated incoherent transport and the concentration of polaronic (mixed) states by composition, and provides experimental access to the polar oxide structure by observing optically induced refractive index inhomogeneities.
Objectives
- Clarification of polaronic mixed states: electron and hole polarons, self-trapped excitons
- Polaronic origin of optically induced refractive index inhomogeneities
- Separation of the coherent/incoherent parts of polaronic transport
- Generalized modelling for polaronic-based, volume photovoltaic effects
