Hall Potential Mapping of Conducting Ferroelectric Domain Walls

By calibration of the AFM signal, an estimate of ~ 1x10¹⁶ cm⁻³ is calculated for the mobile carrier density in the wall, around four orders of magnitude below that required for complete screening of the polar discontinuity. A carrier mobility of ∼ 60cm²V⁻¹s⁻¹ is calculated, about an order of magnitude below equivalent carrier mobilities in p-type silicon, but sufficiently high to preclude carrier-lattice coupling associated with small polarons. <br>The technique was further developed by utilising Kelvin probe force microscopy to map the topographic and electrostatic signal in isolation.

Surface potential mapping of an ErMnO₃ single crystal confirms quantitative accuracy is maintained under a range of magnetic and electric field states, with distinct wall contrast observed at both charged wall types. Lastly, the alternating polarity method was demonstrated as an simple means of signal demodulation to precisely measure the typically minute conductance of individual domain walls.