THEORETICAL-STUDY OF ANOMALOUS INCOMMENSURABILITY IN ALPHA-PHASE URANIUM

The long-standing puzzle concerning the incommensurate structure of alpha-phase uranium is studied theoretically. It is proposed that the domain-boundary region which coherently connects the two variants of the incommensurate charge-density-wave (CDW) states, gives rise to the anomalous diffraction effect. By taking into account the energy associated with spatial variation of the phase factor of the CDW, which couples strongly to the strain, the properties of the domain-boundary region have been studied with a Ginzburg-Landau-type treatment. Particularly, the response of the system against uniaxial stress has been investigated. The results explain consistently the observed diffraction experiments.