  Weak antilocalization measurements has become a standard tool for studying
quantum coherent transport in topological materials. It is often used to
extract information about number of conducting channels and dephasing length of
topological surface states. We study thin films of prototypical topological
crystalline insulator SnTe. To access microscopic characteristic of these
states we employ a model developed by Tkachov and Hankiewicz, [Physical Review
B 84, 035444]. Using this model the spatial decay of the topological states is
obtained from measurements of quantum corrections to the conductivity in
perpendicular and parallel configurations of the magnetic field. Within this
model we find interaction between two topological boundaries which results in
scaling of the spatial decay with the film thickness. We attribute this
behavior to bulk reservoir which mediates interactions by scattering events
without phase breaking of topological carriers.
