SKM 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 4: f-Electron Systems and Heavy Fermions I

TT 4.5: Vortrag

Montag, 27. März 2023, 10:30–10:45, HSZ 201

Quantum spin liquid in an RKKY-coupled two-impurity Kondo system — •Krzysztof P. Wójcik^1,2,3 and Johann Kroha³ — ¹M. Curie-Skłodowska University, 20-031 Lublin, Poland — ²Institute of Molecular Physics, PAS, 60-179 Poznań, Poland — ³Physikalisches Institut, Universität Bonn, 53115 Bonn, Germany

We consider a 2-impurity Anderson model with spin-exchange coupling within the conduction-band sector of the Hamiltonian. Our numerical renormalization group calculations show that for strong intraband spin correlations their competition with the Kondo spin screening stabilizes a metallic spin-liquid phase of the localized spins, even without geometric frustration. It is characterized by nonuniversal impurity spectral density, fractionalization of the phase shift between the local and conduction-band parts, and large but not complete spin-spin correlations. For weak Kondo coupling the spin liquid and the Kondo singlet phase are separated by two quantum phase transitions and an intermediate RKKY spin-dimer phase, while beyond a critical coupling they are connected by a crossover. The results suggest how a quantum spin liquid may be realized in heavy-fermion systems near a spin-density wave instability.