  Rare-earth monopnictide (RE-V) semimetal crystals subjected to hydrostatic
pressure have shown interesting trends in magnetoresistance, magnetic ordering,
and superconductivity, with theory predicting pressure-induced band inversion.
Yet, thus far, there have been no direct experimental reports of interchanged
band order in RE-Vs due to strain. This work studies the evolution of band
topology in biaxially strained GdSb (001) epitaxial films using angle-resolved
photoemission spectroscopy (ARPES) and density functional theory (DFT). We find
that biaxial strain continuously tunes the electronic structure from
topologically trivial to nontrivial, reducing the gap between the hole and the
electron bands dispersing along the [001] direction. The conduction and valence
band shifts seen in DFT and ARPES measurements are explained by a tight-binding
model that accounts for the orbital symmetry of each band. Finally, we discuss
the effect of biaxial strain on carrier compensation and magnetic ordering
temperature.
