Pariari Arnab, Singha Ratnadwip, Roy Shubhankar, Satpati Biswarup, Mandal Prabhat
Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Kolkata, 700 064, India.
Sci Rep. 2018 Jul 12;8(1):10527. doi: 10.1038/s41598-018-28922-9.
TaSb has been predicted theoretically to be a weak topological insulator. Whereas, the earlier magnetotransport experiment has established it as a topological semimetal. In the previous works, the Shubnikov-de Haas oscillation has been analyzed to probe the Fermi surface, with magnetic field along a particular crystallographic axis only. By employing a sample rotator, we reveal highly anisotropic transverse magnetoresistance by rotating the magnetic field along different crystallographic directions. To probe the anisotropy in the Fermi surface, we have performed magnetization measurements and detected strong de Haas-van Alphen (dHvA) oscillations for the magnetic field applied along a and b axes as well as perpendicular to ab plane of the crystals. Three Fermi pockets have been identified by analyzing the dHvA oscillations. With the application of magnetic field along different crystal directions, the cross-sectional areas of the Fermi pockets have been found significantly different, i.e., the Fermi pockets are highly anisotropic in nature. Three-band fitting of electrical and Hall conductivity reveals two high mobility electron pockets and one low mobility hole pocket. The angular variation of transverse magnetoresistance has been qualitatively explained using the results of dHvA oscillations and three-band analysis.
理论预测TaSb是一种弱拓扑绝缘体。然而，早期的磁输运实验已将其确定为拓扑半金属。在之前的工作中，仅沿特定晶轴施加磁场，通过分析舒布尼科夫 - 德哈斯振荡来探测费米面。通过使用样品旋转器，我们通过沿不同晶向旋转磁场揭示了高度各向异性的横向磁阻。为了探测费米面的各向异性，我们进行了磁化测量，并检测到沿晶体的a轴和b轴以及垂直于ab平面施加磁场时的强德哈斯 - 范阿尔芬（dHvA）振荡。通过分析dHvA振荡确定了三个费米口袋。随着沿不同晶体方向施加磁场，发现费米口袋的横截面积显著不同，即费米口袋本质上是高度各向异性的。电导率和霍尔电导率的三带拟合揭示了两个高迁移率电子口袋和一个低迁移率空穴口袋。利用dHvA振荡和三带分析的结果对横向磁阻的角度变化进行了定性解释。
