Evidence for weak collective pinning and δl pinning in topological superconductor Cu _x Bi₂Se₃

We investigated the vortex pinning behavior in the single crystal topological superconductor Cu_0.10Bi₂Se₃ with a pronounced anisotropic peak effect. A weak collective pinning regime is clarified from the power-law behavior in [Formula: see text] and the small critical current density ratio of [Formula: see text] ~ 10^-5 ([Formula: see text] is the critical current density, [Formula: see text] is the depairing current density). The spatial variation of the charge-carrier mean free path induced pinning is evidenced and probably results from the well-defined atomic defects. Within the framework of collective pinning theory, we computed the values of the correlated length and volume at 1.8 K, which start declining prior to the onset field of the peak effect [Formula: see text], demonstrating the vortex lattices already suffered a preferential collapse ahead of the peak effect turns up. Thus, the peak effect can be understood by elastic moduli softening near the upper critical field [Formula: see text]. We suggest Cu _x Bi₂Se₃ is a prototype topological material for investigating the vortex pinning dynamics associated with the peak effect phenomenon.