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碩博班專題討論(Colloquium)

A mechanism for the strange metal phase in rare-earth intermetallic compounds

演講者 : Chung-Hou Chung 仲崇厚 Professor (National Yang Ming Chiao Tung University)
演講時間 : 2022 / 11 / 25 14:10
理學教學新大樓物理系1F 36102教室
理學教學新大樓物理系1F 36102教室 位於....
A major mystery in strongly interacting quantum systems is the microscopic origin of the “strange metal” phenomenology, with unconventional metallic behavior that defies Landau’s Fermi liquid framework for ordinary metals. This state is found across a wide range of quantum materials, notably in rare-earth intermetallic compounds at finite temperatures (T) near a magnetic quantum phase transition, and shows a quasilinear-in-temperature resistivity and a logarithmic-in-temperature specific heat coefficient. Recently, an even more enigmatic behavior pointing toward 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 [1]. 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–stabilized critical (gapless) fermionic spin-liquid metal. It shows ω/T scaling in dynamical electron scattering rate, a signature of quantum criticality. Our results offer a qualitative understanding of the CePd1−xNixAl compound [2] and suggest a possibility of realizing the quantum critical strange metal phase in correlated electron systems in general.

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*This work was supported by the MOST and NCTS of Taiwan, R.O.C.
[1] J. Wang, Y-Y Chang, and C.-H. Chung*, PNAS 119, e2116980119 (2022).
[2] H. Zhao et al., Nat. Phys. 15, 1261–1266 (2019).