How Substitution-induced Defect Scattering Potential influences intervalley quantum interference in Monolayer Tungsten Disulfide

Hao-Yu Chen^2*, Hung-Chang Hsu¹, Jhih-Yuan Liang¹, Bo-Hong Wu¹, Yi-Feng Chen², Chuan-Chun Huang¹, Ming-Yang Li³, Ya-Ping Chiu¹

¹department of physics, National Taiwan University, Taipei, Taiwan
²Graduate School of Advanced Technology, National Taiwan University, Taipei, Taiwan
³Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan

* Presenter:Hao-Yu Chen, email:d11k46001@ntu.edu.tw

Defects in the semiconductor are essential for transport and optoelectronic device technology. However, due to the dimensional confinement effect, two-dimensional transition metal dichalcogenides (TMDs) are more susceptible to atomic defects compared to traditional bulk materials. Therefore, gaining a comprehensive understanding of electron-defect interactions and supporting the development of defect engineering are crucial for advancing TMD-based technologies. In this work, we utilize low-temperature scanning tunneling microscopy (LT-STM) to visualize intervalley quantum interference induced by atomic defects in monolayer tungsten disulfide (WS₂). We observe QPI pattern variations caused by different types of substitutional defects. Additionally, the energy-dependent phase variations in QPI standing waves provide direct insights into the electron scattering rate, defect scattering potential, and carrier mobility. Our findings provide a unique approach to exploring the interplay between atomic defects and carrier transport, with significant implications for future TMD-based technological applications.

Keywords: Transition Metal Dichalcogenides, Scanning Tunneling Microscopy, Defect, Quasiparticle Interference, Phase variation