標題: Mechanism of a strange metal state near a heavy-fermion quantum critical point
作者: Chang, Yung-Yeh
Paschen, Silke
Chung, Chung-Hou
電子物理學系
電機學院
Department of Electrophysics
College of Electrical and Computer Engineering
公開日期: 26-一月-2018
摘要: Unconventional metallic or strange metal (SM) behavior with non-Fermi liquid (NFL) properties, generic features of heavy-fermion systems near quantum phase transitions, are yet to be understood microscopically. A paradigmatic example is the magnetic field-tuned quantum critical heavy-fermion metal YbRh2Si2, revealing a possible SM state over a finite range of fields at low temperatures when substituted with Ge. Above a critical field, the SM state gives way to a heavy Fermi liquid with Kondo correlation. The NFL behavior, most notably a linear-in-temperature electrical resistivity and a logarithmic-in-temperature followed by a power-law singularity in the specific heat coefficient at low temperatures, still lacks a definite understanding. We propose the following mechanism as origin of the experimentally observed behavior: a quasi-2d fluctuating short-ranged resonating-valence-bond spin liquid competing with the Kondo correlation. Applying a field-theoretical renormalization group analysis on an effective field theory beyond a large-N approach to an antiferromagnetic Kondo-Heisenberg model, we identify the critical point and explain remarkably well the SM behavior. Our theory goes beyond the well-established framework of quantum phase transitions and serves as a basis to address open issues in quantum critical heavy-fermion systems.
URI: http://dx.doi.org/10.1103/PhysRevB.97.035156
http://hdl.handle.net/11536/144434
ISSN: 2469-9950
DOI: 10.1103/PhysRevB.97.035156
期刊: PHYSICAL REVIEW B
Volume: 97
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