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Nontrivial fixed points and truncated SU(4) Kondo models in a quasi-quartet multipolar quantum impurity problem
- Source :
- Physical Review B. 104
- Publication Year :
- 2021
- Publisher :
- American Physical Society (APS), 2021.
-
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 YbRu$_{2}$Ge$_{2}$, 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.<br />Comment: 8+8 pages, 2 figures
- Subjects :
- Physics
Strongly Correlated Electrons (cond-mat.str-el)
Field (physics)
Condensed matter physics
Degenerate energy levels
FOS: Physical sciences
Fixed point
Renormalization group
01 natural sciences
010305 fluids & plasmas
Condensed Matter - Strongly Correlated Electrons
0103 physical sciences
Condensed Matter::Strongly Correlated Electrons
Kondo effect
010306 general physics
Ground state
Quantum
Spin-½
Subjects
Details
- ISSN :
- 24699969 and 24699950
- Volume :
- 104
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi.dedup.....82f276936c76e92b3a2367bd9ee3a443