Scanning tunneling microscopy on cleaved Mn₃Sn(0001) surface

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Magnetic Weyl semimetals are a novel class of materials with unique electronic properties.
• Mn3Sn is a promising candidate for spintronic applications due to its magnetic and topological characteristics.
• Understanding surface properties is crucial for device fabrication and performance.

Purpose of the Study:

• To investigate the surface structure and electronic properties of in-situ cleaved Mn3Sn.
• To characterize the atomic and electronic landscape of the magnetic Weyl semimetal.
• To correlate surface morphology with electronic behavior.

Main Methods:

• Low-temperature scanning tunneling microscopy and spectroscopy (STM/S) were employed.
• In-situ cleaving of (0001) surfaces under ultra-high vacuum conditions.
• First-principles calculations were performed to interpret experimental observations.

Main Results:

• Freshly cleaved Mn3Sn surfaces exhibited unknown clusters, requiring voltage pulses for flattening.
• Atomically flat surfaces revealed a bulk-terminated 1x1 honeycomb lattice with Sn sites being the brightest.
• First-principles calculations indicated that surface Mn d orbitals cause the bright contrast at Sn sites.
• Tunneling spectroscopy showed a distinct semimetal valley near the Fermi energy on both as-cleaved and voltage-pulsed surfaces.

Conclusions:

• Achieving atomically flat surfaces of Mn3Sn is possible via voltage pulsing, enabling detailed surface studies.
• The observed surface structure and electronic properties are consistent with a magnetic Weyl semimetal.
• The findings provide fundamental insights into the surface physics of Mn3Sn, relevant for future spintronic devices.