A hybrid topological quantum state in an elemental solid

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Topological Matter

Background:

• Topology and interactions are fundamental to quantum matter.
• Research has explored intertwined phases and topology-interaction interplay, but novel topological orders remain underexplored due to lack of material platforms.

Purpose of the Study:

• To unveil a new 'hybrid' topological phase of matter.
• To investigate the material platform for the coalescence of several topological orders.
• To experimentally demonstrate a conjoined strong and higher-order topology.

Main Methods:

• Tunnelling microscopy
• Photoemission spectroscopy
• Theoretical analysis
• Real-space microscopy
• Momentum-space spectroscopy

Main Results:

• A hybrid topological phase was identified in elemental arsenic.
• Arsenic exhibits a conjoined strong (Z2 invariant) and higher-order topology.
• Topologically induced step-edge conduction channels were observed on arsenic nanostructures.

Conclusions:

• The study provides experimental evidence for hybrid topology in arsenic.
• The findings highlight the unique bulk-surface-edge correspondence in this material.
• This work opens pathways for exploring novel topological phenomena and applications in quantum and nano-devices.