Charge fluctuations in the intermediate-valence ground state of SmCoIn${}_5$

Abstract

The microscopic mechanism of heavy band formation, relevant for unconventional superconductivity in CeCoIn${}_5$ and other Ce-based heavy fermion materials, depends strongly on the efficiency with which $f$ electrons are delocalized from the rare earth sites and participate in a Kondo lattice. Replacing Ce${}^{3+}$ ($4f^1$, $J=5/2$) with Sm${}^{3+}$ ($4f^5$, $J=5/2$), we show that a combination of crystal field and on-site Coulomb repulsion causes SmCoIn${}_5$ to exhibit a ${\Gamma }_7$ ground state similar to CeCoIn${}_5$ with multiple $f$ electrons. Remarkably, we also find that with this ground state, SmCoIn${}_5$ exhibits a temperature-induced valence crossover consistent with a Kondo scenario, leading to increased delocalization of $f$ holes below a temperature scale set by the crystal field, $T_v$ $\approx$ 60 K. Our result provides evidence that in the case of many $f$ electrons, the crystal field remains the most important tuning knob in controlling the efficiency of delocalization near a heavy fermion quantum critical point, and additionally clarifies that charge fluctuations play a general role in the ground state of "115" materials.

arXiv comment12 pages, 5 figures

References in corpus (25)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• A linear response approach to the calculation of the effective interaction parameters in the LDA+U method
• Quantum ESPRESSO toward the exascale
• Hubbard parameters from density-functional perturbation theory
• Use of frit-disc crucibles for routine and exploratory solution growth of single crystalline samples
• Exotic Heavy-Fermion State in Filled Skutterudite SmOs4Sb12
• Time-dependent Density-Matrix Renormalization-Group Methods
• Direct observation of how the heavy fermion state develops in CeCoIn5
• Crystal-field and Kondo scale investigation of CeMIn5 (M=Co, Ir and Rh): a combined x-ray absorption and inelastic neutron study
• Correlation between the phase diagram and the crystal-field wave functions of CeRh(1-x)Ir(x)In5
• Evolution of the Kondo lattice electronic structure above the transport coherence temperature
• Magnetically mediated superconductivity: Crossover from cubic to tetragonal lattice
• Valence Instability and Superconductivity in Heavy Fermion Systems
• Crystal-field ground state of the orthorhombic Kondo insulator CeRu2Al10
• Strong Valence Fluctuation Effects in Sm$T{r}_2$Al${}_{20}$($Tr=$Ti, V, Cr)
• SmB6 Photoemission: Past and Present
• Racah materials: role of atomic multiplets in intermediate valence systems
• Similar temperature scale for valence changes in Kondo lattices with different Kondo temperatures
• Yb Valence Change in (Ce,Yb)CoIn5 from spectroscopy and bulk properties
• Quantitative study of the f occupation in CeMIn5 and other cerium compounds with hard x-rays
• Raman spectroscopy of $f$-electron metals: an example of CeB${}_6$
• Orientation of ground-state orbital in CeCoIn${}_5$ and CeRhIn${}_5$
• Kondo quasiparticle dynamics observed by resonant inelastic x-ray scattering
• Evolution of Magnetic Order from the Localized to the Itinerant Limit

Cited by in corpus (1)

• Flat-band hybridization between $f$ and $d$ states near the Fermi energy of SmCoIn${}_5$