Topologically protected surface states in a centrosymmetric superconductor β-PdBi2

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Topological insulators exhibit unique electronic properties due to their topology.
• Topological superconductors are highly sought after for their potential to host exotic phenomena.
• Developing homogeneous topological superconductors remains a significant challenge.

Purpose of the Study:

• To investigate the presence of topologically protected surface states in the centrosymmetric layered superconductor β-PdBi2.
• To explore the potential of β-PdBi2 as a platform for studying topological superconductivity.

Main Methods:

• Spin- and angle-resolved photoemission spectroscopy (SARPES) was employed to probe the electronic structure.
• Analysis of bulk and surface bands, including their spin polarization.
• Z2 invariant analysis was performed to evaluate the topological nature of the surface states.

Main Results:

• Observation of distinct surface bands in β-PdBi2, in addition to bulk bands.
• Surface bands exhibit symmetrically allowed in-plane spin polarizations.
• Several surface bands were found to cross the Fermi level, indicating their significance.
• The surface states were confirmed to be topological via Z2 invariant analysis.

Conclusions:

• β-PdBi2 hosts topologically protected surface states, confirmed by experimental evidence and theoretical analysis.
• This material presents a promising platform for investigating topological properties within a superconducting condensate.
• The findings contribute to the ongoing development of topological superconductors and related quantum phenomena.