Planar thermal Hall effect from phonons in a Kitaev candidate material

• DOI: 10.48550/arxiv.2309.17231
• Publication Date: 2023-01-01
• Authors: Lu Chen; Étienne Lefrançois; Ashvini Vallipuram; Quentin Barthélemy; Amirreza Ataei; Weiliang Yao; Yuan Li; Louis Taillefer
• Keywords: Thermal Hall effect; Heat current; Magnon

Kitaev materials are a promising platform for the realization of quantum spin liquid states. The thermal Hall effect has emerged as potential probe exotic excitations within such In candidate material $\alpha$-RuCl$_{3}$, however, conductivity $\kappa_{xy}$ been attributed not only to Majorana fermions or chiral magnons, but also phonons. It shown theoretically that former two types heat carriers can generate "planar" effect, whereby magnetic field is parallel current, observed experimentally, it unknown whether phonons could. Here we show planar present in another material, Na$_{2}$Co$_{2}$TeO$_{6}$. On basis striking similarity between temperature and dependence phonon-dominated $\kappa_{xx}$, argue Na$_{2}$Co$_{2}$TeO$_{6}$ generated by phonon contributed shows strong sample dependence, which indicates an extrinsic origin mechanism. By conducting complete study with different in-plane configurations current $J$ $H$, $i.e.$ $H$ $\|$ $\bot$ $J$, observe large difference these configurations, reveals direction may play important role determining effect. Our observation calls re-evaluation $\alpha$-RuCl$_{3}$.