2007/07/10 by Gerd Bergmann, Liye Zhang · 3 citations
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Rare-earth and actinide compounds #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.76.064401
arxiv created 2007/07/10 · openalex publication_date 2007/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A compact approximate ground state of the Kondo problem is introduced. It consists of four Slater states. The spin up and down states of the localized d impurity are paired with two localized s-electron states of opposite spin. All the remaining s-electron states are rearranged, forming two new optimal orthonormal bases. Through a rotation in Hilbert space, the two localized states (and the rest of the bases) are optimized by minimizing the energy expectation value. The ground-state energy E00 and the singlet-triplet excitation energy \ensuremathΔEst are calculated numerically. Although the two energies can differ by a factor of 1000, they are obtained simultaneously. The singlet-triplet excitation energy \ensuremathΔEst is proportional to exp[\ensuremath-1∕2J\ensuremathρ] and quite close to the Kondo temperature kBTK. The cases for antiferromagnetic (J>0) and ferromagnetic (J<0) couplings are investigated.