We investigate the interplay between strong on-site electronic correlations and disorder in the CrMnFeCoNi high-entropy alloy, focusing on their impact on electronic transport and optical properties [1]. This study combines experimental techniques such as resonant photoemission spectroscopy (ResPES) and valence band photoemission spectroscopy (PES) with density functional theory (DFT) calculations using the Korringa-Kohn-Rostoker Green’s function method [2]. Many-body effects beyond the Local Density Approximation (LDA) are included via dynamical mean-field theory (DMFT)[3].

Using the Chini-Sawatzky framework for Auger-like signals, we analyze element-resolved ResPES data to estimate the on-site Coulomb repulsion (U ) of the 3d electrons for each alloy component. Our findings demonstrate that the on-site Coulomb interactions in the alloy mirror those of the constituent pure elements. Linear response calculations within the Kubo framework [4] reveal that the imaginary part of the self-energy for localized d-band electrons significantly influences the optical absorption in the visible to ultraviolet range, achieving remarkable agreement with experimental data. Furthermore, in electrical resistivity, chemical and magnetic disorder dominate at low temperatures [5], whereas at elevated temperatures, reduced quasiparticle lifetimes increasingly contribute to transport properties. We conclude that in disordered and correlated alloys, many-body effects predominantly influence states at higher binding energies, while chemical disorder strongly smears bands near the Fermi level. These findings advance our understanding of the intricate relationship between electronic correlations and disorder in high-entropy alloys.

References:
[1] David Redka, Saleem Ayaz Khan, Edoardo Martino, Xavier Mettan, Luka Ciric , Davor Tolj , Trpimir Ivšić , Andreas Held , Marco Caputo , Eduardo Bonini Guedes , Vladimir N. Strocov , Igor Di Marco , Hubert Ebert , Heinz P. Huber , J. Hugo Dil , László Forró, Ján Minár, Nature Comm., vol. 15, 7983 (2024)
[2] H. Ebert, D. Kodderitzsch, and J. Minár, “Calculating Condensed Matter Properties Using the KKR-Green’s Function Method—Recent Developments and Applications,” Reports on Progress in Physics, vol. 74, p. 096501, 2011.
[3] J. Minár, “Correlation Effects in Transition Metals and Their Alloys Studied Using the Fully Self-Consistent KKR-Based LSDA + DMFT Scheme,” J. Phys.: Condens. Matter, vol. 23, p. 253201, 2011.
[4] T. Huhne and H. Ebert, “Fully Relativistic Description of the Magneto-Optical Properties of Arbitrary Layered Systems,” Phys. Rev. B, vol. 60, p. 12982, 1999.
[5] Y. Zhang et al., “Influence of Chemical Disorder on Energy Dissipation and Defect Evolution in Advanced Alloys,” J. Mater. Res., vol. 31, p. 2363, 2016.