Boulanger Marie-Eve, Grissonnanche Gaël, Badoux Sven, Allaire Andréanne, Lefrançois Étienne, Legros Anaëlle, Gourgout Adrien, Dion Maxime, Wang C H, Chen X H, Liang R, Hardy W N, Bonn D A, Taillefer Louis
Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada.
SPEC, CEA, CNRS-UMR3680, Université Paris-Saclay, Gif-Sur-Yvette, France.
Nat Commun. 2020 Oct 21;11(1):5325. doi: 10.1038/s41467-020-18881-z.
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of the cuprate Mott insulator LaCuO were recently shown to be phonons. However, the mechanism by which phonons in cuprates acquire chirality in a magnetic field is still unknown. Here, we report a similar thermal Hall conductivity in two cuprate Mott insulators with significantly different crystal structures and magnetic orders - NdCuO and SrCuOCl - and show that two potential mechanisms can be excluded - the scattering of phonons by rare-earth impurities and by structural domains. Our comparative study further reveals that orthorhombicity, apical oxygens, the tilting of oxygen octahedra and the canting of spins out of the CuO planes are not essential to the mechanism of chirality. Our findings point to a chiral mechanism coming from a coupling of acoustic phonons to the intrinsic excitations of the CuO planes.
负责铜酸盐莫特绝缘体LaCuO出现意外大的热霍尔电导率的热载流子最近被证明是声子。然而，铜酸盐中的声子在磁场中获得手性的机制仍然未知。在这里，我们报道了在两种具有显著不同晶体结构和磁序的铜酸盐莫特绝缘体——NdCuO和SrCuOCl中存在类似的热霍尔电导率，并表明两种潜在机制可以被排除——稀土杂质和声子对结构域的散射。我们的比较研究进一步揭示，正交性、顶氧、氧八面体的倾斜以及自旋从CuO平面的倾斜对手性机制并非至关重要。我们的研究结果指向一种来自声学声子与CuO平面本征激发耦合的手性机制。
