A mechanism for strange metal phase in rare-earth inter-metallic compounds
Jiangfan Wang1, Yung-Yeh Chang1,2*, Chung-Hou Chung1,2
1Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
2Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
* Presenter:Yung-Yeh Chang, email:cdshjtr@gmail.com
A major mystery in strongly interacting quantum systems is the microscopic origin of "strange metal", with unconventional metallic behavior that defies the Landau’s Fermi liquid framework for ordinary metals. This state is found across a wide range of quantum materials, notably in rare-earth inter-metallic compounds at finite temperatures (T) near a magnetic quantum phase transition, and shows a quasi-linear-in-temperature resistivity and a logarithmic-in-temperature specific heat coefficient. Recently, an even more enigmatic behavior pointing towards a stable strange metal ground-state was observed in CePd1−xNixAl, a geometrically frustrated Kondo lattice compound. Here, we propose a mechanism for such phenomena driven by the interplay of the gapless fermionic short-ranged antiferromagnetic spin correlations (spinons) and critical bosonic charge (holons) fluctuations near a Kondo breakdown quantum phase transition. Within a dynamical large-N approach to the Kondo-Heisenberg lattice model, the strange metal phase is realized in transport and thermodynamical quantities. It is manifested as a fluctuating Kondo-scattering-stablized critical (gapless) fermionic spin-liquid metal. It shows ω/T scaling in dynamical electron scattering rate, signature of quantum criticality. Our results offer a qualitative understanding of CePd1−xNixAl compound and suggest a possibility of realizing quantum critical strange metal phase in correlated electron systems in general.

Keywords: Strange metal, quantum criticality, heavy fermion