|
A Cd-Yb alloy rich in order-disorder transition � clue to an understanding of the nature of quasicrystalline icosahedral lattice �Apr. 4, 2006Unlike ordinary metals with translational periodic lattices, quasicrystals have icosahedral lattice components which pile up to form successively larger icosahedral units and eventually fill the three dimensional space without translational periodicity. The inner core clusters of Cd tetrahedrons in the Cd-Yb alloy, which is an approximant to its quasicrystal form, are randomly oriented at ambient pressure and temperature. The single-crystal X-ray diffraction measurements have revealed that the Cd-Yb alloy exhibits various types of ordering or disordering in the orientation of the Cd tetrahedron sensitively depending on pressure-temperature condition; eight phases appear at the range of 0-5 GPa and 5-300 K. The P-T sensitive transition behavior is attributed to the correlations between the neighboring Cd tetrahedra presumably through itinerant electrons: a new type of electron-lattice interaction. Further comparison study of Cd-Yb quasicrystal structure at the corresponding P-T region will lighten the essential nature of quasicrystalline icosahedral lattice. •A Cd-Yb alloy rich in order-disorder transition at high pressure and low temperature |
