Thermal Hall Conductivity in Cuprates
ORAL
Abstract
Thermal Hall conductivity (kxy) has been used to characterize the pseudogap phase of hole-doped cuprates [1]. A new and unexpected result was found: the presence of a negative thermal Hall signal appearing in the pseudogap phase, which grows as the sample becomes insulating, being maximal in the Mott insulator La2CuO4. The heat carriers responsible for that large thermal Hall conductivity were shown to be phonons [2].
The microscopic mechanism that confers chirality on phonons remains to be discovered. To shed light on this, we measured kxy in two additional Mott insulators, Nd2CuO4 and Sr2CuO2Cl2. This comparative study [3] shows that a large kxy is still present in those Mott insulators, ruling out mechanisms such as apical oxygen, spin canting or structural domains. Strong similarities in the temperature dependence and relative magnitude of kxy and kxx provide further evidence that it is indeed the phonons that are responsible for kxy in those materials. A possible mechanism of chirality could be the coupling of phonons to short-range antiferromagnetic correlations.
[1] G. Grissonnanche et al. Nature 571, 376 (2019).
[2] G. Grissonnanche et al. Nature Physics, arXiv:2003.00111 (2020).
[3] M-E. Boulanger et al. Nature Communications 11, 5325 (2020).
The microscopic mechanism that confers chirality on phonons remains to be discovered. To shed light on this, we measured kxy in two additional Mott insulators, Nd2CuO4 and Sr2CuO2Cl2. This comparative study [3] shows that a large kxy is still present in those Mott insulators, ruling out mechanisms such as apical oxygen, spin canting or structural domains. Strong similarities in the temperature dependence and relative magnitude of kxy and kxx provide further evidence that it is indeed the phonons that are responsible for kxy in those materials. A possible mechanism of chirality could be the coupling of phonons to short-range antiferromagnetic correlations.
[1] G. Grissonnanche et al. Nature 571, 376 (2019).
[2] G. Grissonnanche et al. Nature Physics, arXiv:2003.00111 (2020).
[3] M-E. Boulanger et al. Nature Communications 11, 5325 (2020).
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Presenters
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Marie-Eve Boulanger
- Universite de Sherbrooke (Canada)
- Universite de Sherbrooke