Topological chiral crystals with helicoid-arc quantum states

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Quantum behavior of electrons is fundamental to electronics and information technology.
• Topological quantum materials are crucial for quantized electronic responses and advanced technologies.
• Chiral crystals possess unique structural properties that can lead to novel electronic phenomena.

Purpose of the Study:

• To report the first observation of topological quantum properties in chiral crystals of the RhSi family.
• To investigate the electronic and optical properties arising from the structural chirality of these materials.
• To characterize the unique surface states and their topological significance.

Main Methods:

• Experimental observation of topological quantum properties.
• Characterization of electronic band structure and surface states.
• Analysis of crystal symmetries and their implications for topological invariants.

Main Results:

• First observation of topological quantum properties in RhSi chiral crystals.
• Identification of a quantum phase with nearly ideal topological surface properties.
• Discovery of unusual helicoid fermionic surface states indicating electronic topological chirality.
• Observation of giant Fermi arcs (maximum length π) with topological charges of ±2.
• Demonstration of an electronic topological state of matter on structurally chiral crystals.

Conclusions:

• The RhSi family of chiral crystals hosts a novel electronic topological state.
• These materials exhibit unique helicoid-arc quantum states with significant topological charges.
• The observed giant Fermi arcs are unprecedented in known chiral Weyl fermion semimetals.
• These findings open avenues for exploring quantized photogalvanic optical response and other optoelectronic phenomena.