Unidirectional Magneto-Resistance in Modulation-Doped Magnetic Topological Insulators

Journal Article · 28 January 2019 · Nano Letters

DOI: https://doi.org/10.1021/acs.nanolett.8b03702 · OSTI ID:1566552

Fan, Yabin ^[1]; Shao, Qiming  ^[2]; Pan, Lei ^[2]; Che, Xiaoyu  ^[2]; He, Qinglin ^[2]; Yin, Gen ^[2]; Zheng, Cheng ^[2]; Yu, Guoqiang  ^[2]; Nie, Tianxiao  ^[3]; Masir, Massoud R. ^[4]; MacDonald, Allan H. ^[4]; Wang, Kang L.  ^[2]

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1. Univ. of California, Los Angeles, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2. Univ. of California, Los Angeles, CA (United States)
3. Beihang Univ., Beijing (China)
4. Univ. of Texas, Austin, TX (United States)

Nonlinear unidirectional spin Hall magnetoresistance (USMR) has been reported in heavy metal/ferromagnet bilayers, which could be employed as an effective method in detecting the magnetization orientation in spintronic devices with 2-terminal geometry. Recently, another unidirectional magnetoresistance (UMR) was reported in magnetic topological insulator (TI)-based heterostructures at cryogenic temperature, whose amplitude is orders of magnitude larger than the USMR measured in heavy metal-based magnetic heterostructures at room temperature. Here, we report the UMR effect in the modulation-doped magnetic TI structures. This UMR arises due to the interplay between the magnetic dopant’s magnetization and the current-induced surface spin polarization, when they are parallel or antiparallel to each other in the TI material. By varying the dopant’s position in the structure, we reveal that the UMR is mainly originating from the interaction between the magnetization and the surface spin-polarized carriers (not bulk carriers). Furthermore, from the magnetic field-, the angular rotation-, and the temperature-dependence, we highlight the correlation between the UMR effect and the magnetism in the structures. The large UMR versus current ratio in TI-based magnetic bilayers promises the easy readout in TI-based spintronic devices with 2-terminal geometry.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Spins and Heat in Nanoscale Electronic Systems (SHINES); Univ. of California, Riverside, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: SC0012670
• OSTI ID: 1566552
• Journal Information: Nano Letters, Journal Name: Nano Letters Journal Issue: 2 Vol. 19; ISSN 1530-6984
• Publisher: American Chemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English