Temperature-sensitive spatial distribution of defects in PdSe2 flakes

TL;DR

This study reveals that temperature can dynamically reconfigure the spatial distribution of defects in PdSe2 flakes, affecting their electronic transport properties and opening new avenues for defect engineering in van der Waals materials.

Contribution

We demonstrate temperature-dependent defect redistribution in PdSe2 flakes and its impact on electronic transport, a novel approach to defect engineering in 2D materials.

Findings

Defect distribution in PdSe2 is anisotropic at 80 K.

Raising temperature weakens defect anisotropy.

Electrical transport properties are sensitive to defect redistribution.

Abstract

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.