Long Period Polytypes - LPP’s
Sample J108 model: 15R+6H+LPP+6H+1DD+6H classified as an American club sandwich
1DD layer measured as 30 µm thick
Defect bands present at all boundaries
Long period polytypes appear as closer spaced reflections between the low period common polytypes 6H, 15R, 4H. Altogether 20 of the 135 crystals in the data set contain a measurable LPP as distinct from a 1DD layer.