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DOE OSTI · 2588795

Tuning the electronic properties of MgB 2 by substitution with Mn and C

Adriano, Cris [Iowa State Univ., Ames, IA (United States); Univ. of Campinas (UNICAMP), Sao Paulo (Brazil); Univ. of Sherbrooke, QC (Canada)] (ORCID:0000000158368631)·Xu, Mingyu [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States); Michigan State Univ., East Lansing, MI (United States)] (ORCID:0000000171386009)·Huyan, Shuyuan [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000309992440)·Pakuszewski, Kevin R. [Univ. of Sherbrooke, QC (Canada)] (ORCID:0000000275509982)·Machado, Alisson P. [Univ. of Campinas (UNICAMP), Sao Paulo (Brazil)]·Schrunk, Benjamin [Iowa State Univ., Ames, IA (United States)]·Bud′ko, Sergey L. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000236035585)·Ribeiro, Raquel A. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000160751701)·Canfield, Paul C. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000277150643)·Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000211707875)
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Abstract

We use high-resolution angle-resolved photoemission spectroscopy (ARPES) to investigate the electronic band structure of the superconductors Mg 0.995 Mn 0.005 B 2 and Mg(B 0.98 C 0.02 ) 2 , in comparison with pristine MgB 2 . Our experimental findings reveal modest changes in the size of the Fermi surface sheets following manganese or carbon substitution, with the most pronounced effect observed in the outermost σ band. Additionally, the dispersion kink, indicative of strong renormalization due to the interaction between conduction electrons and phonon modes near −0.065 eV, remains unaffected by chemical substitution. Given that the superconducting transition temperature decreases significantly more rapidly in Mn-substituted MgB 2 than in C-substituted MgB 2 , our ARPES results strongly suggest that the primary mechanism behind the pronounced T C suppression in Mn–MgB 2 is the disruption of Cooper pairs via Abrikosov–Gorkov spin-flip scattering caused by the local magnetic moments of Mn.

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Adriano, Cris [Iowa State Univ., Ames, IA (United States); Univ. of Campinas (UNICAMP), Sao Paulo (Brazil); Univ. of Sherbrooke, QC (Canada)] (ORCID:0000000158368631), Xu, Mingyu [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States); Michigan State Univ., East Lansing, MI (United States)] (ORCID:0000000171386009), Huyan, Shuyuan [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000309992440), Pakuszewski, Kevin R. [Univ. of Sherbrooke, QC (Canada)] (ORCID:0000000275509982), Machado, Alisson P. [Univ. of Campinas (UNICAMP), Sao Paulo (Brazil)], Schrunk, Benjamin [Iowa State Univ., Ames, IA (United States)], Bud′ko, Sergey L. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000236035585), Ribeiro, Raquel A. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000160751701), Canfield, Paul C. [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000277150643), Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Ames Laboratory (AMES), Ames, IA (United States)] (ORCID:0000000211707875). 2025-07-28. Tuning the electronic properties of MgB 2 by substitution with Mn and C. https://doi.org/10.1088/1361-648x%2Fadeb27

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