Phonon Thermal Hall Effect: The Roles of Disorder, Annealing, and Metallic Contacts

Abstract

The phonon thermal Hall effect (THE) is a ubiquitous yet poorly understood phenomenon in insulators. Its microscopic origin remains debated, partly due to significant sample-dependent variations that hint at uncontrolled experimental parameters. Using SrTiO${}_3$ as a model system, we identify disorder and uncontrolled strain as suppressors of a thermal Hall signal. Crystals with high thermal conductivity exhibit a substantial thermal Hall angle $\nabla T_y/\nabla T_x$ (up to 0.3\% at 9 T), whereas the effect is virtually absent in disordered samples. Crucially, annealing (in air atmosphere) these disordered samples partially restores the THE (approximately 0.1\% at 9 T) with little effect on the longitudinal thermal conductivity. This decoupling reveals that the amplitude of THE is not simply set by the phonon mean free path. Furthermore, measurements performed with metallic and insulating contacts yield identical results on the same sample. This definitively rules out parasitic signals as the effect's origin. Our work, by establishing the phonon THE as an intrinsic property of the crystal lattice and extremely sensitive to disorder, sharply constrains theoretical scenarios.

arXiv comment9 pages, 4 figures

References in corpus (34)

• Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquid
• Observation of the Magnon Hall Effect
• Valley contrasting chiral phonons in monolayer hexagonal lattices
• Topological Nature of the Phonon Hall Effect
• Thermal Hall conductivity in the frustrated pyrochlore magnet Tb2Ti2O7
• Berry Curvature and Phonon Hall Effect
• Giant thermal Hall conductivity from neutral excitations in the pseudogap phase of cuprates
• Phonons become chiral in the pseudogap phase of cuprates
• Theory of Phonon Hall Effect in Paramagnetic Dielectrics
• Thermal transport and phonon hydrodynamics in strontium titanate
• Phonon thermal Hall effect in strontium titanate
• Sample dependence of the half-integer quantized thermal Hall effect in the Kitaev candidate $\alpha$-RuCl${}_3$
• Anomalous Hall effect for the phonon heat conductivity in paramagnetic dielectric
• Emergence of nontrivial magnetic excitations in a spin liquid state of kagome volborthite
• Thermal Hall effect in a phonon-glass Ba${}_3$CuSb${}_2$O${}_9$
• Enhanced thermal Hall effect in nearly ferroelectric insulators
• Large Phonon Thermal Hall Conductivity in a Simple Antiferromagnetic Insulator
• The phonon thermal Hall angle in black phosphorus
• Universal behavior of the thermal Hall conductivity
• Charged Defects and Phonon Hall Effects in Ionic Crystals
• Resonant thermal Hall effect of phonons coupled to dynamical defects
• Phonon thermal Hall effect in a metallic spin ice
• Phonon drag thermal Hall effect in metallic strontium titanate
• Sizeable suppression of thermal Hall effect upon isotopic substitution in strontium titanate
• Phonon Hall effect in ionic crystals in the presence of static magnetic field
• Large extrinsic phonon thermal Hall effect from resonant scattering
• Phonon thermal transport shaped by strong spin-phonon scattering in a Kitaev material Na${}_2$Co${}_2$TeO${}_6$
• Impurity-induced phonon thermal Hall effect in the antiferromagnetic phase of Sr2IrO4
• Phonon thermal Hall effect in charge-compensated topological insulators
• Planar thermal Hall effect from phonons in cuprates
• Magnetothermal transport in ultraclean single crystals of Kitaev magnet $\alpha$-RuCl${}_3$
• Influence of ferroelastic domain walls on thermal conductivity
• Phonon thermal Hall as a lattice Aharonov-Bohm effect
• Angle-dependent planar thermal Hall effect by quasi-ballistic phonons in black phosphorus