Ferroelectric domains and material contrast down to a 5 nm lateral resolution on uniaxial ferroelectric triglycine sulphate crystals

We operate dynamic force microscopy (DFM) in non-contact mode under ultrahi gh vacuum conditions in order to differentiate local chemical inhomogeneiti es from ferroelectric domains in bulk single crystals of triglycine sulphat e (TGS), Individual layers of both mixed glycine and sulphate, and pure gly cine ions are resolved resulting in a lateral material contrast of 5 nm and a sub-unit cell vertical contrast. The clue information is deduced when an alysing the excitation amplitude A(exc) applied to the piezo shaker in cons tant amplitude DFM which is strongly affected either by the short-range che mical force or the longer range electrostatic contribution. The latter aris es from the bound surface charge within individual ferroelectric domains an d results in a long-range tip-sample interaction. From variation of the bia s voltage applied to the TGS counter electrode we deduce the sign of the bo und surface charge within each ferroelectric domain. Hence, domain walls th at separate regions of antiparallel polarization are resolved down to a 9 n m domain wall width. Copyright (C) 1999 John Wiley & Sons, Ltd.