Atomic structure and lattice defects in nanolaminated ternary transition metal borides

We use analytical aberration-corrected high-resolution scanning transmission electron microscopy to image the atomic structure of the layered ternary transition metal (M) borides, Cr2AlB2, Fe2AlB2, and MoAlB. In these ternaries, MB layers and Al single or double atomic layers are interleaved. The atomic positions of the M elements and Al are clearly resolved by Z-contrast images. The following structural defects are also found and described herein: a 90 degrees twist boundary along [010] in Cr2AlB2, a tilt boundary in Fe2AlB2, and Mo2AlB2-like stacking faults in MoAlB, where some of the MB-based structures are intercalated by one (instead of two) Al layer(s).Funding Agencies|Swedish Research Council; Knut and Alice Wallenberg Foundation [KAW 2008-0058, KAW 2011-0143, KAW 2015.0043]; Leverhulme Trust; Army Research Office [W911NF-11-1-0525]