Abstract
Structural investigations by means of transmission electron microscopy (TEM) on FeSe and KFeSe, with 1.5 ⩽ ⩽ 1.8, have revealed a rich variety of microstructure phenomena. Materials with 1.5 ⩽ ⩽ 1.6 often show a superstructure modulation along the [310] zone-axis direction, and this modulation can be well interpreted by the Fe-vacancy order, which likely yields a superstructure phase of FeSe. The superconducting FeSe and KFeSe (1.7 ⩽ ⩽ 1.8) materials contain clear phase separation, in particular, along the -axis direction, recognizable as visible parallel lamellae in the crystals; this fact suggests that the superconducting phase could have the Fe-vacancy disordered state.
- Received 8 March 2011
- Corrected 20 April 2011
DOI:https://doi.org/10.1103/PhysRevB.83.140505
©2011 American Physical Society
Corrections
20 April 2011