Mt

Large negative thermal Hall response in the pseudogap phase of cuprates

date
20.12.2018 
time
11:00 AM - 12:30 PM 
speaker
Gaël Grissonnanche 
affiliation
Université de Sherbrooke, Canada 
language
en 
main topic
Materials: general
host
Prof. E. Hassinger 
abstract

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).

 

Last update: 16.12.2018 00:07.

venue 

Max-Planck-Institut für Chemische Physik fester Stoffe (Seminarraum 1+2, Nöthnitzer Straße 40, 01187 Dresden) 
Nöthnitzer Straße 40
01187 Dresden
e-mail
Max-Planck-Institut für Chemische Physik fester Stoffe 
homepage
http://www.cpfs.mpg.de/ 

organizer 

Max-Planck-Institut für Chemische Physik fester Stoffe (MPI-CPfS)
Nöthnitzer Straße 40
01187 Dresden
e-mail
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI-CPfS) 
homepage
http://www.cpfs.mpg.de/ 
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