  The Fermi surface topology of the shape-memory alloy Ni[0.62]Al[0.38] has
been determined using Compton scattering. A large area of this Fermi surface
can be made to nest with other areas by translation through a vector of ~ 0.18
[1,1,0] (2pi/a), which correponds to the wavevector associated with martensitic
precursor phenomena such as phonon softening and diffuse streaking in electron
diffraction patterns. This observation is compelling evidence that these
phenomena are driven by the enhanced electron-lattice coupling due to the Fermi
surface nesting.
