  Martensites are materials that undergo diffusionless, solid-state
transitions. The martensitic transition yields properties that depend on the
history of the material and may allow it to recover its previous shape after
plastic deformation. This is known as the shape-memory effect (SME). We have
succeeded in identifying the primary electronic mechanism responsible for the
martensitic transition in the shape-memory alloy AuZn by using Fermi-surface
measurements (de Haas-van Alphen oscillations) and band-structure calculations.
This strongly suggests that electronic band structure is an important
consideration in the design of future SME alloys.
