2020/04/23 by Naoum Karchev, Karchev, Naoum
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Quantum, superfluid, helium dynamics #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2004.11179
openalex publication_date 2020/04/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a unified theory of magnetism and superconductivity of UGe2. To this end, we consider part of 5f uranium electrons as mostly itinerant and other ones as mostly localized. The main feature that distinguishes the localized from the itinerant electrons is the effect of the pressure on them. The pressure strongly screens the itinerant electrons while the localized ones are almost unaffected. The screening of itinerant electrons leads to decreasing of their Coulomb repulsion, therefore to formation of doubly occupied and empty states. These states are spin-singlet and the effective spin of itinerant electrons, the zero-temperature magnetization in units of Bohr magneton, decreases. We obtain an effective two-spin Heisenberg model, which explains the magnetization-temperature diagram of UGe2. It is shown that the experimentally observed characteristic temperature Tx, is a partial order transition temperature. Below the Curie temperature (Tx