Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable...

Area of Science:

• Solid State Physics
• Surface Science
• Quantum Mechanics

Background:

• Photoemission spectroscopy is a key technique for probing electronic structures.
• Understanding spin-orbit coupling is crucial for advanced materials.
• Characterizing spin states in materials requires advanced spectroscopic methods.

Purpose of the Study:

• To present a protocol for spin- and angle-resolved photoemission spectroscopy (SARPES) using a polarization-variable 7-eV laser (laser-SARPES).
• To demonstrate the capabilities of laser-SARPES for studying solid-state physics.
• To investigate spin-orbit coupled surface states of Bi2Se3 using this advanced technique.

Main Methods:

• Utilizing a polarization-variable 7-eV laser in conjunction with SARPES.
• Employing orbital selection rules of linearly polarized lasers for selective excitation.
• Direct spin detection combined with polarization-variable laser control.

Main Results:

• Laser-SARPES enables orbital-selective excitation by examining laser polarization-dependent selection rules.
• The technique provides comprehensive information on the variation of the spin quantum axis with light polarization.
• Decomposition of spin and orbital components from spin-orbit coupled wavefunctions was achieved.
• Unambiguous three-dimensional visualization of light polarization dependence of the spin quantum axis was demonstrated.

Conclusions:

• Laser-SARPES significantly enhances the capabilities of photoemission techniques.
• This method offers powerful insights into spin-orbit coupled phenomena in materials.
• The technique provides a detailed understanding of spin dynamics and electronic structure.