A spectroscopic-imaging scanning tunneling microscope in vector magnetic field.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Investigating quantum materials requires atomic precision to understand complex electronic and magnetic properties.
• Anisotropic superconductivity and spin physics are crucial phenomena influenced by magnetic fields and material structure.
• Existing techniques often lack the capability to probe these properties under precisely controlled, variable magnetic field orientations.

Purpose of the Study:

• To design, construct, and demonstrate a novel cryogenic scanning tunneling microscope (STM) system with vector magnet capabilities.
• To enable atomic-resolution imaging and spectroscopy of surface magnetic structures and electronic properties in quantum materials.
• To explore spin physics and anisotropic superconductivity under precisely controlled, multi-directional magnetic fields.

Main Methods:

• Development of an ultra-high-vacuum (UHV) cryogenic STM operating from 1.5 K to 300 K.
• Integration of a 3 Tesla vector magnet allowing magnetic field application in any direction relative to the sample.
• Sample preparation techniques including cleaving and UHV transfer, alongside in-situ tip treatment.

Main Results:

• Successful construction and operation of the UHV cryogenic STM with vector magnet.
• Demonstrated capability to image surface structures and perform spectroscopy while varying magnetic field direction.
• Verified performance for studying materials with significant magnetic anisotropy.

Conclusions:

• The developed cryogenic STM/STS facility offers unprecedented capabilities for atomic-scale investigation of quantum materials.
• This system is ideal for studying materials where magnetic anisotropy dictates electronic properties, such as topological semimetals and superconductors.
• Provides a powerful new tool for advancing research in spin physics and anisotropic superconductivity.