Gutzwiller variational approach to the two-impurity Anderson model for a metallic host at particle-hole symmetry. (12th October 2017)

• Record Type: Journal Article
• Authors: Linneweber, Thorben; Bünemann, Jörg; Mahmoud, Zakaria M M; Gebhard, Florian
• Is Part Of: Journal of physics. Volume 29:Number 44(2017)
• Publication Date: 2017-10-12
• Subjects: impurity scattering -- RKKY interaction -- Gutzwiller wave function; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa89d1
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We study Gutzwiller-correlated wave functions as variational ground states for the two-impurity Anderson model (TIAM) at particle-hole symmetry as a function of the impurity separation R . Our variational state is obtained by applying the Gutzwiller many-particle correlator to a single-particle product state. We determine the optimal single-particle product state fully variationally from an effective non-interacting TIAM that contains a direct electron transfer between the impurities as variational degree of freedom. For a large Hubbard interaction U between the electrons on the impurities, the impurity spins experience a Heisenberg coupling proportional to V 2 / U where V parameterizes the strength of the on-site hybridization. For small Hubbard interactions we observe weakly coupled impurities. In general, for a three-dimensional simple cubic lattice we find discontinuous quantum phase transitions that separate weakly interacting impurities for small interactions from singlet pairs for large interactions.