Geometry-Induced Spin Filtering in Photoemission Maps from WTe_{2} Surface States

Area of Science:

• Condensed Matter Physics
• Quantum Materials Science
• Surface Science

Background:

• Tungsten Ditelluride (WTe$_{2}$) is a quantum material known for its exotic transport properties.
• Low-symmetry materials often exhibit unique electronic and spin-related phenomena.
• Understanding spin behavior in photoemission is crucial for advanced electronic devices.

Purpose of the Study:

• To investigate a novel geometry-induced spin filtering effect in WTe$_{2}$.
• To explore the relationship between material symmetry and spin textures in photoemission.
• To understand the origins of exotic transport properties in low-symmetry quantum materials.

Main Methods:

• Utilized laser-driven spin-polarized angle-resolved photoemission spectroscopy.
• Performed Fermi surface mapping to analyze electron spin textures.
• Employed theoretical modeling within the one-step photoemission model.

Main Results:

• Demonstrated a significant geometry-induced spin filtering effect in WTe$_{2}$ photoemission.
• Observed highly asymmetric spin textures in photoemitted electrons from surface states.
• Showcased that these asymmetries differ from initial state spin textures, which are symmetry-bound.

Conclusions:

• The observed spin filtering effect is a manifestation of time-reversal symmetry breaking during photoemission.
• The effect originates from the material's low crystal symmetry and can be understood via interference in the final state model.
• This phenomenon cannot be eliminated but can be influenced by experimental geometry, offering control over spin filtering.