Fig. 1: Selection rules for activation of DW sliding modes under the electric field applied by the SMIM tip.
From: Domain wall-localized phonons in BiFeO3: spectrum and selection rules
a Excitation of a DW sliding mode is allowed when the field favors one of the domains; b, c when the field from the tip has the same projection on the polarizations of two domains, the excitation of the DW sliding mode is forbidden. c 71° domain wall corresponding to the P2 reversal in BFO. The wall is tilted to minimize the elastic energy due to strain mismatch between the two domains, thus breaking the mirror indicated with a dashed line. The pseudocubic coordinates x1, x2, x3 shown here are used throughout the paper and are referred to as the horizontal, out-of-plane and vertical directions.
