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z = 3 antiferromagnetic quantum criticality driven by the Kondo effect
1Asia Pacific Center for Theoretical Physics, Hogil Kim Memorial building 5th floor, POSTECH, Hyoja-dong, Namgu, Pohang 790-784, Korea.
Physical Review Letters
|May 21, 2010
Summary
The Kondo effect establishes a new universality class for antiferromagnetic quantum critical points in heavy fermion systems. This finding explains non-Fermi liquid behaviors and aligns with experimental data for YbRh2Si2.
Area of Science:
- Condensed Matter Physics
- Quantum Critical Phenomena
- Heavy Fermion Systems
Background:
- Antiferromagnetic (AF) quantum critical points (QCPs) in heavy fermion systems are crucial for understanding exotic quantum phases.
- The role of the Kondo effect in defining universality classes at AF QCPs remains an active area of research.
Purpose of the Study:
- To investigate the universality class of an antiferromagnetic quantum critical point driven by the Kondo effect in heavy fermion systems.
- To determine the theoretical framework describing the thermodynamics and transport properties associated with this QCP.
Main Methods:
- Theoretical analysis of heavy fermion models incorporating the Kondo effect.
- Identification of deconfined bosonic spinons as key excitations.
- Calculation of critical exponents and thermodynamic/transport properties.
Main Results:
- The Kondo effect leads to a new universality class for the AF QCP with a dynamical exponent z=3.
- Thermodynamics and transport exhibit non-Fermi liquid behavior, including a Grüneisen ratio exponent of 2/3 and linear resistivity.
- A characteristic uniform spin susceptibility divergence exponent of 2/3 is predicted.
Conclusions:
- The z=3 AF QCP provides a consistent theoretical framework for observed non-Fermi liquid physics in heavy fermion materials.
- The predicted spin susceptibility exponent matches experimental findings for YbRh2Si2, supporting the Kondo-driven QCP model.
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