Quantum impurity model for two-stage multipolar ordering and Fermi surface reconstruction
2025.01.06 11:18
| 날짜 | 2025-01-08 16:00 |
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| 연사 | Dr. SangEun Han |
| 장소 | E6, #3441 |
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세미나/특강명 |
Quantum impurity model for two-stage multipolar ordering and Fermi surface reconstruction |
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연사명 |
Dr. SangEun Han |
소속기관 및 직위 |
Simon Fraser University / Postdoctoral Fellow |
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개최 일시 |
2025.01.08 16:00 |
개최 장소 |
E6, 3441호 |
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활용 교수 |
문은국 |
Abstract:
Classification and understanding of quantum phase transitions and critical phenomena in itinerant electron systems are outstanding questions in
quantum materials research. Recent experiments on heavy fermion systems with higher-rank multipolar local moments provide a new platform
to study such questions. In particular, experiments on Ce3Pd20(Si,Ge)6 show novel quantum critical behaviors via two consecutive magnetic
field-driven quantum phase transitions. At each transition, the derivative of the Hall conductivity jumps discontinuously, which was attributed to
sequential Fermi surface reconstructions. Motivated by this discovery, we consider an effective quantum impurity model of itinerant electrons
coupled to local dipolar, quadrupolar, and octupolar moments arising from Ce3+ ions. Using renormalization group analyses, we demonstrate that two-stage multipolar ordering and Fermi surface reconstruction arise depending on which multipolar moments participate in the Fermi surface and which other moments are decoupled via Kondo destruction.
Contact: Eun Gook Moon(egmoon@kaist.ac.kr)
