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Phonon thermal Hall effect in a metallic spin ice
Taiki Uehara1, Takumi Ohtsuki2, Masafumi Udagawa1
1Department of Physics, Gakushuin University, Tokyo, 171-8588, Japan.
Nature Communications
|August 6, 2022
Summary
Phonons, not charge carriers, dominate thermal conductivity in Pr2Ir2O7. Spin-phonon scattering impedes heat flow and generates the thermal Hall effect, clarifying a long-standing controversy.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Thermodynamics
Background:
- The thermal Hall effect, driven by phonons, is observed in various materials but its mechanism remains debated.
- Pr2Ir2O7, a metallic analog of spin ice, provides a unique system to investigate spin-phonon interactions in thermal transport.
Purpose of the Study:
- To elucidate the role of phonons and spin-phonon interactions in longitudinal (κxx) and transverse (κxy) thermal conductivity of Pr2Ir2O7.
- To investigate the influence of magnetic field and temperature on thermal transport properties.
Main Methods:
- Measurement of longitudinal and transverse thermal conductivity (κxx and κxy) in Pr2Ir2O7 under varying temperatures and magnetic fields.
- Analysis of T/H scaling behavior of κxx to identify phonon scattering mechanisms.
Main Results:
- Phonons, not mobile charge carriers, were found to dominate both κxx and κxy.
- Resonant scattering of phonons on paramagnetic spins significantly impedes longitudinal heat current, as evidenced by T/H scaling of κxx.
- Spin ice correlations at low temperatures altered resonant scattering, causing anisotropic deviations in κxx.
- κxy showed a strong correlation with κxx in response to magnetic fields, including shared scaling behaviors and deviations.
Conclusions:
- Spin-phonon scattering plays a crucial role in both hindering longitudinal heat conduction and generating the transverse thermal Hall response in Pr2Ir2O7.
- The findings provide strong evidence for the significant contribution of spin-phonon interactions to thermal transport phenomena in magnetic materials.
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