Enhanced Kondo Effect in an Electron System Dynamically Coupled with Local Optical Phonon

Abstract

We discuss Kondo behavior of a conduction electron system coupled with local optical phonon by analyzing the Anderson-Holstein model with the use of a numerical renormalization group (NRG) method. There appear three typical regions due to the balance between Coulomb interaction $U_{\mathrm{ee}}$ and phonon-mediated attraction $U_{\mathrm{ph}}$. For $U_{\mathrm{ee}}>U_{\mathrm{ph}}$, we observe the standard Kondo effect concerning spin degree of freedom. Since the Coulomb interaction is effectively reduced as $U_{\mathrm{ee}}-U_{\mathrm{ph}}$, the Kondo temperature $T_{\mathrm{K}}$ is increased when $U_{\mathrm{ph}}$ is increased. On the other hand, for $U_{\mathrm{ee}}<U_{\mathrm{ph}}$, there occurs the Kondo effect concerning charge degree of freedom, since vacant and double occupied states play roles of pseudo-spins. Note that in this case, $T_{\mathrm{K}}$ is decreased with the increase of $U_{\mathrm{ph}}$. Namely, $T_{\mathrm{K}}$ should be maximized for $U_{\mathrm{ee}}\approx U_{\mathrm{ph}}$. Then, we analyze in detail the Kondo behavior at $U_{\mathrm{ee}}=U_{\mathrm{ph}}$, which is found to be explained by the polaron Anderson model with reduced hybridization of polaron and residual repulsive interaction among polarons. By comparing the NRG results of the polaron Anderson model with those of the original Anderson-Holstein model, we clarify the Kondo behavior in the competing region of $U_{\mathrm{ee}}\approx U_{\mathrm{ph}}$.

8 pages, 8 figures

References in corpus (15)

• Inelastic electron tunneling via molecular vibrations in single-molecule transistors
• Time-dependent Density-Matrix Renormalization-Group Methods
• Exotic Heavy-Fermion State in Filled Skutterudite SmOs4Sb12
• Many Body Effects on the Transport Properties of Single-Molecule Devices
• Kondo resonances and anomalous gate dependence of electronic conduction in single-molecule transistors
• Heavy Fermion Behavior, Crystalline Electric Field Effects, and Weak Ferromagnetism in SmOs_{4}Sb_{12}
• Local Heavy Quasiparticle in Four-Level Kondo Model
• Quantum transport through a deformable molecular transistor
• Phonon softening and double-well potential formation due to electron-phonon interaction in heavy-fermion systems
• Quasi-Kondo Phenomenon due to Dynamical Jahn-Teller Effect
• Magnetoconductance through a vibrating molecule in the Kondo regime
• Kondo Effect in an Electron System with Dynamical Jahn-Teller Impurity
• Realization of Strong Coupling Fixed Point in Multilevel Kondo Models
• Multipole Susceptibility of Multiorbital Anderson Model Coupled with Jahn-Teller Phonons
• Microscopic Aspects of Multipole Properties of Filled Skutterudites

Cited by in corpus (15)

• Quantum phases driven by strong correlations
• Thermopower enhancement by encapsulating cerium in clathrate cages
• Electronic Transport through Magnetic Molecules with Soft Vibrating Modes
• Effect of Rattling Phonons on Sommerfeld Constant
• Theory of Defect-Induced Kondo Effect in Graphene: Numerical Renormalization Group Study
• Inverse Isotope Effect on Kondo Temperature in Electron-Rattling System
• Theory of Charge Kondo Effect on Pair Hopping Mechanism
• Strong-Coupling Theory of Rattling-Induced Superconductivity
• Cooperative Effect of Coulomb Interaction and Electron-Phonon Coupling on the Heavy Fermion State in the Two-Orbital Periodic Anderson Model
• Periodic Anderson model with electron-phonon correlated conduction band
• Heavy-Electron Formation and Bipolaronic Transition in the Anharmonic Holstein Model
• Electric Dipolar Susceptibility of the Anderson-Holstein Model
• Kondo Effect of a Jahn-Teller Ion Vibrating in a Cubic Anharmonic Potential
• Chaos in Jahn-Teller Rattling
• Particle-hole Symmetric Slave Boson Method for the Mixed Valence Problem