  We report on a direct measurement of cation and anion sub-lattice strain in
an InAs/GaSb type-II strained layer superlattice (T2SLs) using atomic
resolution Z-contrast imaging and advanced image processing. Atomic column
positions in InAs and GaSb are determined by separating the cation and anion
peak intensities. Analysis of the InAs/GaSb T2SLs reveals the compressive
strain in the nominal GaSb layer and tensile strain at interfaces between
constituent layers, which indicate In incorporation into the nominal GaSb layer
and the formation of GaAs like interfaces, respectively. The results are
compared with the model-dependent X-ray diffraction measurements in terms of
interfacial chemical intermixing and strain. Together, these techniques provide
a robust measurement of atomic-scale strain which is vital to determine T2SL
properties.
