Large Carrier Mobilities in ErMnO3 Conducting Domain Walls Revealed by Quantitative Hall Effect Measurements

Kelvin Probe Force Microscopy (KPFM) has been used to directly and quantitatively measure Hall voltages, developed at conducting tail-to-tail domain walls in ErMnO3 single crystals, when current is driven in the presence of an approximately perpendicular magnetic field. Measurements across a number of walls, using two different atomic force microscope platforms, consistently suggest that the active p-type carriers have unusually large room temperature mobilities: of the order of hundreds of square centimetres per volt second (cm2V-1s-1); associated carrier densities were estimated to be of the order of 1013cm-3. Such mobilities, at room temperature, are high in comparison to both bulk oxide conductors and LaAlO3-SrTiO3 sheet conductors. High carrier mobilities are encouraging for the future of domain-wall nanoelectronics and, significantly, also suggest the feasibility of meaningful investigations into dimensional confinement effects in these novel domain wall systems.