Seeing the Fermi surface in real space by nanoscale electron focusing

Area of Science:

• Condensed Matter Physics
• Surface Science
• Materials Science

Background:

• Imaging the Fermi surface, crucial for understanding electronic band structure in solids, often lacks spatial resolution for local variations.
• Traditional methods struggle to visualize nanoscale electronic properties and subsurface features.

Purpose of the Study:

• To demonstrate a novel method for real-space imaging of Fermi surfaces.
• To utilize subsurface point scatterers for mapping local electronic properties and buried defects.

Main Methods:

• Employing low-temperature scanning tunneling microscopy (STM).
• Introducing cobalt impurities as subsurface point scatterers beneath a copper surface.
• Analyzing charge density oscillations induced by electron scattering.

Main Results:

• Successfully imaged Fermi surfaces in real space using STM with subsurface scatterers.
• Observed anisotropic electron propagation on the nanoscale due to copper's Fermi surface.
• Demonstrated the capability to map buried defects and interfaces via induced charge density oscillations.

Conclusions:

• Subsurface point scatterers enable real-space Fermi surface imaging with STM.
• This technique offers a new pathway for characterizing nanoscale electronic properties and subsurface structural details.