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

Abstract

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, taken 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 centimeters per volt second. Associated carrier densities were estimated to be of the order of 10¹³ cm^-3. Such mobilities, at room temperature, are high in comparison with 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.