講演情報
[18p-D61-1]Giant Odd-parity Magnetoresistance in an α-Sn / (In,Fe)Sb Heterostructure
〇Harunori Shiratani1, Yuta Okuyama1, Le Duc Anh1,2, Masaaki Tanaka1,2 (1.Department of Electrical Engineering and Information Systems, The Univ. of Tokyo, 2.CSRN, The Univ. of Tokyo)
キーワード：
Ferromagnetic semiconductor、Spintronics
The magnetoresistance is usually an even function of a magnetic field according to Onsager’s theorem. However, when time reversal symmetry (TRS) is broken, the magnetoresistance may have an odd-function component of a magnetic field. This phenomenon is called odd-parity magnetoresistance (OMR). OMR is theoretically predicted to occur in Weyl semimetals (WSM) with tilted Weyl cones. WSM is characterized by the spin-splitting Dirac cone (Weyl cones) and may be achieved by introducing TRS breaking such as magnetization into topological Dirac semimetals (TDS). Here, we focus on α-Sn / (In1-x,Fex)Sb heterostructures, where α-Sn is known as a TDS, while (In1-x,Fex)Sb is a ferromagnetic semiconductor (FMS). In this heterostructure, the TRS in α-Sn is expected to be broken by the magnetic proximity effect from the magnetization of underlying (In1-x,Fex)Sb, enabling us to observe OMR.
In this study, an α-Sn / (In1-x,Fex)Sb heterostructure was grown by molecular beam epitaxy. The sample structure was (from top to bottom) AlOx (3 nm) / α-Sn (6.5 nm) / (In1-x,Fex)Sb (x = 15%, 20 nm) / InSb (100 nm) on an InSb (001) substrate. When a magnetic field Bwas applied parallel to the current, we observe a giant OMR as large as 170 % at B = 1 T, 5.5 K. Moreover, the signs of OMR are different when being measured at the opposite edges, which suggests that the OMR occurs in the transport channels at the Hall bar edges. The origin of this OMR might be explained by opposite tilting of the Weyl cones at the opposite edges. This large OMR possibly provides a deeper insight into MPE in topological materials and practical spintronic applications.
In this study, an α-Sn / (In1-x,Fex)Sb heterostructure was grown by molecular beam epitaxy. The sample structure was (from top to bottom) AlOx (3 nm) / α-Sn (6.5 nm) / (In1-x,Fex)Sb (x = 15%, 20 nm) / InSb (100 nm) on an InSb (001) substrate. When a magnetic field Bwas applied parallel to the current, we observe a giant OMR as large as 170 % at B = 1 T, 5.5 K. Moreover, the signs of OMR are different when being measured at the opposite edges, which suggests that the OMR occurs in the transport channels at the Hall bar edges. The origin of this OMR might be explained by opposite tilting of the Weyl cones at the opposite edges. This large OMR possibly provides a deeper insight into MPE in topological materials and practical spintronic applications.
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