Large negative thermal Hall conductivity in cuprate Mott insulators

Marie-Eve Boulanger; Gael Grissonnanche; Maxime Dion; Etienne Lefrancois; Ruixing Liang; Walter N Hardy; Douglas A Bonn; Jianshi Zhou; Louis Taillefer

Large negative thermal Hall conductivity in cuprate Mott insulators

ORAL

Abstract

A large negative thermal Hall signal k_xy has recently been observed to appear in the pseudogap phase of cuprates [1]. This signal persists to zero doping, in the antiferromagnetic Mott insulator La₂CuO₄. While it is clearly not due to electrons, this k_xy signal could come from magnons, or phonons — or more exotic excitations. To shed light on the underlying mechanism, we measured k_xy in two additional cuprate Mott insulators: Nd₂CuO₄ and Sr₂CuO₂Cl₂ . We observe a large negative k_xysignal in both materials. Because of the absence of spin canting in either of these materials without apical oxygens, and because of the absence of any change in k_xyupon crossing different magnetic states in Nd₂CuO₄, we infer that magnons are not the heat carriers responsible for k_xy. The similarity in the temperature dependence of k_xy and k_xx suggests a phonon scenario. If so, the mechanism whereby the pseudogap phase confers chirality to phonons remains to be elucidated.

[1] Grissonnanche et al., Nature 571, 376 (2019).

March 3, 2020, 10:36 AM – March 3, 2020, 10:48 AM

Presenters

Marie-Eve Boulanger

Universite de Sherbrooke, University of Sherbrooke

Authors

Marie-Eve Boulanger

Universite de Sherbrooke, University of Sherbrooke
Gael Grissonnanche

Universite de Sherbrooke, University of Sherbrooke
Maxime Dion

Universite de Sherbrooke
Etienne Lefrancois

Universite de Sherbrooke
Ruixing Liang

Department of Physics & Astronomy, University of British Columbia, University of British Columbia, University of British Colombia
Walter N Hardy

Department of Physics & Astronomy, University of British Columbia, University of British Colombia
Douglas A Bonn

University of British Columbia, University of British Colombia
Jianshi Zhou

Geological Sciences, University of Texas at Austin, Department of Mechanical Engineering, The University of Texas at Austin, Walker Department of Mechanical Engineering, University of Texas at Austin, Department of Mechanical Engineering, University of Texas at Austin, The University of Texas at Austin, University of Texas at Austin, University of Texas, Materials Science and Engineering program, Department of Mechanical Engineering, University of Texas at Austin
Louis Taillefer

Universite de Sherbrooke, University of Sherbrooke