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Thermal Hall and Nernst responses in ultrathin magnetic films of pyrochlore lattice

Sheikhi, B ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1088/1361-648X/abf976
  3. Publisher: IOP Publishing Ltd , 2021
  4. Abstract:
  5. The ultrathin films of pyrochlore lattice along [111] direction provide a fertile ground for exploring topological states in oxide materials, where the electron correlations are strong and magnetically ordered states are favored. As a result of strong interactions, most of states are magnetic insulators with strong Dzyaloshinskii–Moriya and anisotropic spin interactions. We considered three types of heterostructures, a bilayer of triangular-kagome (TK), and two trilayers of triangular-kagome-triangular (TKT) and kagome-triangular-kagome (KTK) thin films. The ground states are magnetically ordered with the low-energy excitations, the magnons, characterized by nontrivial topology. While for TK model the lowest magnon band is trivial, the lowest bands in TKT and KTK model are topological. These features have direct consequences on the thermal Hall conductivity, where we observed that the latter quantity onsets at lower temperature in multilayer models, suggesting that the thermal Hall response can be controlled by engineering lattice-driven magnetic band structure. We also introduce the thermal sublattice Nernst effect in these layers and found the corresponding response is as large as the thermal Hall response. © 2021 IOP Publishing Ltd
  6. Keywords:
  7. Crystal lattices ; Film preparation ; Ground state ; Magnetism ; Oxide films ; Topology ; Ultrathin films ; Low-energy excitations ; Lower temperatures ; Magnetic insulator ; Magnetically ordered state ; Nontrivial topology ; Pyrochlore lattices ; Strong interaction ; Ultra thin magnetic films ; Thermal Engineering
  8. Source: Journal of Physics Condensed Matter ; Volume 33, Issue 26 , 2021 ; 09538984 (ISSN)
  9. URL: https://iopscience.iop.org/article/10.1088/1361-648X/abf976