Zooming in on heavy fermions in Kondo lattice models

Abstract

Resolving the heavy fermion band in the conduction electron momentum resolved spectral function of the Kondo lattice model is challenging since, in the weak coupling limit, its spectral weight is exponentially small. In this article we consider a composite fermion operator, consisting of a conduction electron dressed by spin fluctuations that shares the same quantum numbers as the electron operator. Using approximation free auxiliary field quantum Monte Carlo simulations we show that for the SU(2) spin-symmetric model on the square lattice at half filling, the composite fermion acts as a magnifying glass for the heavy fermion band. In comparison to the conduction electron residue that scales as $e^{-W/J_k}$ with $W$ the bandwidth and $J_k$ the Kondo coupling, the residue of the composite fermion tracks $J_k$. This result holds down to $J_k/W=0.05$, and confirms the point of view that magnetic ordering, present below $J_k/W=0.18$, does not destroy the heavy quasiparticle. We furthermore investigate the spectral function of the composite fermion in the ground state and at finite temperatures, for SU($N$) generalizations of the Kondo lattice model, as well as for ferromagnetic Kondo couplings, and compare our results to analytical calculations in the limit of high temperatures, large-$N$, large-$S$, and large $J_k$. Based on these calculations, we conjecture that the composite fermion operator provides a unique tool to study the destruction of the heavy fermion quasiparticle in Kondo breakdown transitions. The relation of our results to scanning tunneling spectroscopy and photoemission experiments is discussed.

16 pages, 14 figures, typos corrected

References in corpus (11)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Fractionalized Fermi liquids
• Visualizing heavy fermions emerging in a quantum critical Kondo lattice
• Electron Cotunneling into a Kondo Lattice
• Orbital-selective Mott transitions: Heavy fermions and beyond
• Identifying the maximum entropy method as a special limit of stochastic analytic continuation
• Fermi surface topology of the two-dimensional Kondo lattice model: a dynamical cluster approximation approach
• Signature of quantum criticality in photoemission spectroscopy at elevated temperature
• Low-energy properties of the Kondo lattice model
• Luttinger sum rules and spin fractionalization in the SU(N) Kondo Lattice
• Antiferromagnetic phase of the Kondo-insulator

Cited by in corpus (17)

• Controlled bond expansion for DMRG ground state search at single-site costs
• Spin chain on a metallic surface: Dissipation-induced order vs. Kondo entanglement
• Artificially built Kondo chains with organic radicals on metallic surfaces: new model system of heavy fermion quantum criticality
• Breakdown of heavy quasiparticles in a honeycomb Kondo lattice: A quantum Monte Carlo study
• Matrix Product Study of Spin Fractionalization in the 1D Kondo Insulator
• Altermagnetism in Heavy Fermion Systems: Mean-Field study on Kondo Lattice
• A Simple Solvable Model for Heavy Fermion Superconductivity from the Two-Fluid Normal State
• Nonlocal Kondo effect and two-fluid picture revealed in an exactly solvable model
• Marginal Fermi liquid at magnetic quantum criticality from dimensional confinement
• Magnetic quantum phase transition in a metallic Kondo heterostructure
• Instanton gas approach to the Hubbard model
• SU($\mathbf{N}$) Kondo-Heisenberg chain: Phase diagram, Ising criticality, and the coexistence of heavy quasiparticles and valence bond solid order
• Lieb-Schultz-Mattis constraints for the insulating phases of the one-dimensional SU($N$) Kondo lattice model
• Spin fractionalization in a Kondo-lattice superconductor heterostructure
• Quantum Fisher information in a strange metal
• Solution of one-dimensional Kondo lattice model, ground state calculation
• Phases and phase transitions of an $S=3/2$ chain on metallic and semi-metallic surfaces