  Defect engineering plays an important role in tailoring the electronic
transport properties of van der Waals materials. However, it is usually
achieved through tuning the type and concentration of defects, rather than
dynamically reconfiguring their spatial distribution. Here, we report
temperature-sensitive spatial redistribution of defects in PdSe2 thin flakes
through scanning tunneling microscopy (STM). We observe that the spatial
distribution of Se vacancies in PdSe2 flakes exhibits a strong anisotropic
characteristic at 80 K, and that this orientation-dependent feature is weakened
when temperature is raised. Moreover, we carry out transport measurements on
PdSe2 thin flakes and show that the anisotropic features of carrier mobility
and phase coherent length are also sensitive to temperature. Combining with
theoretical analysis, we conclude that temperature-driven defect spatial
redistribution could interpret the temperature-sensitive electrical transport
behaviors in PdSe2 thin flakes. Our work highlights that engineering spatial
distribution of defects in the van der Waals materials, which has been
overlooked before, may open up a new avenue to tailor the physical properties
of materials and explore new device functionalities.
