Surface barrier dominated transport in NbSe${}_2$

Transport current distribution in clean 2$H$-NbSe${}_2$ crystals is studied by measuring the self-induced magnetic field across the sample. Below $T_c$ most of the current flows at the edges of the crystals due to strong surface barriers, which are found to dominate the transport properties and the resistive transition. The measured critical current is determined by the critical current for vortex penetration through the surface barrier rather than by bulk pinning.