Compositionally Complex Alloys: Some Insights from Photoemission Spectroscopy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Compositionally complex alloys (CCA), including high-entropy alloys (HEA), are a significant class of advanced materials.
• Understanding the electronic structure of CCAs is vital for predicting and controlling their intrinsic properties.
• Photoemission spectroscopy (PES) is an underutilized technique for investigating CCA electronic structures.

Purpose of the Study:

• To highlight the importance and application of PES in studying CCAs.
• To demonstrate how PES can elucidate the electronic structure and properties of CCAs.
• To present specific examples of PES applications in alloy research.

Main Methods:

• Photoemission spectroscopy (PES) was employed to probe the electronic structure of various CCAs.
• Techniques included analyzing valence band (VB) structures, density of states (DOS) at the Fermi level, and constituent contributions.
• Specific alloy systems studied include transition metal alloys and Cantor-type alloys.

Main Results:

• PES revealed differences between split-band and common-band structures in the valence band, explaining alloy properties.
• High-accuracy PES determined the variation in the density of states at the Fermi level with Cu content in Ti-Zr-Nb-Ni-Cu metallic glasses.
• Initial results demonstrated the ability to isolate the electronic contributions of individual elements in Cantor-type alloys.

Conclusions:

• PES is essential for a comprehensive understanding of CCA electronic structure and properties.
• The analysis of VB structures and constituent contributions using PES provides valuable insights into alloy behavior.
• PES offers a powerful approach for materials design and discovery in the field of advanced alloys.