Non-Trivial Fixed Points and Truncated SU(4) Kondo Models in a Quasi-Quartet Multipolar Quantum Impurity Problem
arXiv:2104.11245 · doi:10.1103/PhysRevB.104.125144
Abstract
The multipolar Kondo problem, wherein the quantum impurity carries higher-rank multipolar moments, has seen recent theoretical and experimental interest due to proposals of novel non-Fermi liquid states and the availability of a variety of material platforms. The multipolar nature of local moments, in conjunction with constraining crystal field symmetries, leads to a vast array of possible interactions and resulting non-Fermi liquid ground states. Previous works on Kondo physics have typically focussed on impurities that have two degenerate internal states. In this work, inspired by recent experiments on the tetragonal material YbRuGe, which has been shown to exhibit a local moment with a quasi-fourfold degenerate ground state, we consider the Kondo effect for such a quasi-quartet multipolar impurity. In the tetragonal crystal field environment, the local moment supports dipolar, quadrupolar, and octupolar moments, which interact with conduction electrons in entangled spin and orbital states. Using renormalization group analysis, we uncover a number of emergent quantum ground states characterized by non-trivial fixed points. It is shown that these previously unidentified fixed points are described by truncated SU(4) Kondo models, where only some of the SU(4) generators (representing the impurity degrees of freedom) are coupled to conduction electrons. Such novel non-trivial fixed points are unique to the quasi-quartet multipolar impurity, reinforcing the idea that an unexplored rich diversity of phenomena may be produced by multipolar quantum impurity systems.
arXiv comment8+8 pages, 2 figures
References in corpus (22)
- Heavy Fermions and Quantum Phase Transitions
- Multiple Superconducting Phases in New Heavy Fermion Superconductor PrOs4Sb12
- Kondo effect in quantum dots
- Description of Multipole in f-Electron Systems
- Quantum phase transitions in heavy fermion metals and Kondo insulators
- Transition from overscreening to underscreening in the multichannel Kondo model: exact solution at large N
- Kondo screening cloud in the single-impurity Anderson model: A density matrix renormalization group study
- Single-Site Non-Fermi Liquid Behaviors in a Diluted 4 System YPrIrZn
- Quasiquartet CEF ground state with possible quadrupolar ordering in the tetragonal compound YbRuGe
- Logarithmic Corrections in Quantum Impurity Problems
- On The Multichannel Kondo Model"
- Fermi/non-Fermi mixing in SU() Kondo effect
- Revealing the nature of antiferro-quadrupolar ordering in Cerium Hexaboride: CeB
- Critical theory of non-Fermi liquid fixed point in multipolar Kondo problem
- Intermediate coupling fixed point study in the overscreened regime of generalized multichannel SU(N) Kondo models
- Emergent non-Fermi-liquid phenomena in multipolar quantum impurity systems
- Lattice dynamics, crystal-field excitations and quadrupolar fluctuations of YbRuGe
- Unveiling Quadrupolar Kondo Effect in the Heavy Fermion Superconductor PrVAl
- Unconventional Superconductivity arising from Multipolar Kondo Interactions
- Rise and Fall of Non-Fermi Liquid Fixed Points in Multipolar Kondo Problems
- Quantum Criticality and Dynamical Kondo Effect in an SU(2) Anderson Lattice Model
- Electronic structure of the quadrupolar ordered heavy-fermion compound YbRu2Ge2 measured by angle-resolved photoemission