Schwinger boson approach to the Kondo lattice model

Jiangfan Wang^1*, Yung-Yeh Chang¹, Chung-Yu Mou², Stefan Kirchner³, Silke Paschen⁴, Chung-Hou Chung¹

¹Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
²Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
³Department of Physics, Zhejiang University, Hangzhou, China
⁴Institute of Solid State Physics, Vienna University of Technology, Vienna, Austria

* Presenter:Jiangfan Wang, email:wangjiangfan2012@gmail.com

The microscopic mechanism of the heavy-fermion systems close to anti-ferromagnetic quantum critical point constitutes an outstanding open problem in correlated electron systems. To address this issue, we employ a distinct route from the dynamical mean-field theory by solving the 2D Kondo-Heisenberg model via a dynamical large-N multichannel Schwinger boson approach. We identify the quantum critical point separating the anti-ferromagnetic long-ranged ordered and the heavy Kondo-screened Fermi-liquid phases. Various thermodynamical observables near criticality show non-Fermi liquid behaviors and agree qualitatively well with the experiments seen in CeCu_6-xAu_x and YbRh₂Si₂.

Keywords: Heavy fermion, Non-Fermi liquid, Quantum critical point, Schwinger boson