Where Is the Unmatched Transition Metal in Substoichiometric Diboride Line Compounds?
<div>The atomic structure and local composition of high quality epitaxial substoichiometric titanium</div><div>diboride (TiB<sub>1.9</sub>) thin film, deposited by unbalanced magnetron sputtering, were studied using</div><div>analytical high-resolution scanning transmission electron microscopy, density functional theory</div><div>and image simulations. The unmatched Ti is pinpointed to planar defects on {1-100} prismatic</div><div>planes and attributed to the absence of B between Ti planes that locally relaxes the structure.</div><div>This mechanism allows the line compound to accommodate the off-stoichiometry and remain</div><div>a line compound between defects. The planar defects are embedded in otherwise stoichiometric</div><div>TiB<sub>2</sub> and are delineated by insertion of dislocations. An accompanied decrease in Ti-Ti bond</div><div>lengths along and across the faults is observed.</div><div>Introduction</div>
