Large negative thermal Hall response in the pseudogap phase of cuprates

Date

Dec 20, 2018

Time

11:00 AM - 12:30 PM

Speaker

Gaël Grissonnanche

Affiliation

Université de Sherbrooke, Canada

Language

en

Main Topic

Materialien

Other Topics

Materialien

Host

Prof. E. Hassinger

Description

The nature of the pseudogap phase of cuprate superconductors remains a mystery. In that phase, the Fermi surface is transformed even though translational symmetry is not broken [1]. A possible explanation is a spin-liquid-like state with topological order [2]. The thermal Hall conductivity κxy has recently emerged as a powerful probe of insulators with unusual forms of magnetism, such as quantum spin liquids [3] and quantum spin ice [4]. We report extensive measurements of the thermal Hall conductivity κxy in several families of cuprates across a wide range of dopings. We observe a large and negative thermal Hall response at temperatures below the pseudogap temperature T*, which appears immediately below the pseudogap critical doping p*. The negative κxy contrasts with the positive electrical Hall conductivity σxy and, moreover, the magnitude of κxy increases as doping is reduced towards p = 0, whereas σxy vanishes as the material becomes an insulator. The negative κxy is therefore due to neutral heat carriers and it points to spin chirality [5], or perhaps topological excitations. [1] Proust & Taillefer, Annu. Rev. Condens. Matter Phys. (in press); arXiv:1804.08502 (2018). [2] Scheurer et al., PNAS 115, E3665 (2018). [3] Kasahara et al., Nature 559, 227 (2018). [4] Hirschberger et al., Science 348, 6230 (2015). [5] Lee et al., PRB 91, 125413 (2015).

Links

• MPI CPfS

Last modified: Dec 21, 2018, 1:09:58 AM