"barn door" or "barn door track") or ask your local retailer who sells parts for building sheds and/or barns. Here are some that I've found online...
Specialty Doors (used by The Pioneer woman)
anyone know of source for barn door style
reclaimed regular door made into barn door slider
Converted swinging door into sliding door.
old door used as a slider - good idea!!!
maybe a door like this ( old
love this vintage door as slider for closet
looks like an old school door used barn door style. Interesting.
fantastic old door would make entering any room an extraordinary experience.
Have an old, vintage door in need of a home? Replace your boring accordion closet doors with it! I love how this door grounds the feel of rustic, cottage charm that this bedroom embraces.