Structure defects of icosahedral quasicrystals as electrically active centres

By dilatometric experiments on rapidly quenched quasicrystalline Al–Cu–Fe, in the course of their annealing it is proposed that icosahedral (I-) phases with free carriers of different signs (either electrons or holes) have different senses of the volume changes upon ordering. The effect discovered serves as a direct experimental support that the structural defects in I-quasicrystals are electrically active centers. This circumstance allows the identification of intrinsic and extrinsic properties of I-phases and opens novel opportunities for understanding the physical properties of real quasicrystals.