It is shown that in L1(2) ordered compounds due to the interaction bet
ween the superpartials a Paidar-Pope-Vitek (PPV) lock has a higher ene
rgy than the planar glissile configuration, when both are in their rel
axed equilibrium configuration. Hence PPV locks are intrinsically unst
able. Using typical material parameters for Ni3Al it is shown that gen
erally the driving forces on the cube plane are also not large enough
to produce stable PPV locks during deformation.