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arXiv · 1901.08908

Current-Induced Torques with Dresselhaus Symmetry Due to Resistance Anisotropy in 2D Materials

Gregory M. Stiehl·David MacNeill·Nikhil Sivadas·Ismail El Baggari·Marcos H. D. Guimaraes·Neal D. Reynolds·Lena F. Kourkoutis·Craig J. Fennie·Robert A. Buhrman·Daniel C. Ralph
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Abstract

We report measurements of current-induced torques in heterostructures of Permalloy (Py) with TaTe$_2$, a transition-metal dichalcogenide (TMD) material possessing low crystal symmetry, and observe a torque component with Dresselhaus symmetry. We suggest that the dominant mechanism for this Dresselhaus component is not a spin-orbit torque, but rather the Oersted field arising from a component of current that flows perpendicular to the applied voltage due to resistance anisotropy within the TaTe$_2$. This type of transverse current is not present in wires made from a single uniform layer of a material with resistance anisotropy, but will result whenever a material with resistance anisotropy is integrated into a heterostructure with materials having different resistivities, thereby producing a spatially non-uniform pattern of current flow. This effect will therefore influence measurements in a wide variety of heterostructures incorporating 2D TMD materials and other materials with low crystal symmetries.

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Gregory M. Stiehl, David MacNeill, Nikhil Sivadas, Ismail El Baggari, Marcos H. D. Guimaraes, Neal D. Reynolds, Lena F. Kourkoutis, Craig J. Fennie, Robert A. Buhrman, Daniel C. Ralph. 2019-01-25. Current-Induced Torques with Dresselhaus Symmetry Due to Resistance Anisotropy in 2D Materials. https://doi.org/10.1021/acsnano.8b09663

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