Singular charge fluctuations at a magnetic quantum critical point

L Prochaska; X Li; D C MacFarland; A M Andrews; M Bonta; E F Bianco; S Yazdi; W Schrenk; H Detz; A Limbeck; Q Si; E Ringe; G Strasser; J Kono; S Paschen

doi:10.1126/science.aag1595

Singular charge fluctuations at a magnetic quantum critical point

Science. 2020 Jan 17;367(6475):285-288. doi: 10.1126/science.aag1595.

Authors

L Prochaska^#¹, X Li^#², D C MacFarland^#^{1

3}, A M Andrews³, M Bonta⁴, E F Bianco⁵, S Yazdi⁶, W Schrenk⁷, H Detz⁷, A Limbeck⁴, Q Si⁸, E Ringe⁶, G Strasser^{3

7}, J Kono^{2

6

8}, S Paschen^{9

8}

Affiliations

¹ Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria.
² Department of Electrical and Computer Engineering, 6100 Main Street, Rice University, Houston, TX 77005, USA.
³ Institute of Solid State Electronics, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria.
⁴ Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria.
⁵ Department of Chemistry, 6100 Main Street, Rice University, Houston, TX 77005, USA.
⁶ Department of Materials Science and Nanoengineering, 6100 Main Street, Rice University, Houston, TX 77005, USA.
⁷ Center for Micro- and Nanostructures, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria.
⁸ Department of Physics and Astronomy, Center for Quantum Materials, 6100 Main Street, Rice University, Houston, TX 77005, USA.
⁹ Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria. [email protected].

^# Contributed equally.

PMID: 31949077
DOI: 10.1126/science.aag1595

Abstract

Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxy-grown thin films of YbRh₂Si₂, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't

Abstract

Publication types

Grants and funding