Disorder in Staging of Potassium Graphite: Fractional Stage 3/2 and STAGE 7

Abstract

ABSTRACTAt high pressure KC8 undergoes a staging transition to a mixture of stages 1 and 3/2 at 15 kbar and stages 1 and 2 at 19 kbar. The width of the new peaks are not resolution limited but show a pronounced and non-monotonic variation with Q. This broadening is the result of a finite concentration of staging defects which can be simply modeled by stochastic disordering of an appropriately chosen two component layer sequence. This same analysis has also been used to explain deviations from the Bragg locations in KC84.