Shi Shuyuan

@article{ISI:000663272500001,
title = {Observation of the Out-of-Plane Polarized Spin Current from CVD Grown WTe_{2}},
author = {Shuyuan Shi and Jie Li and Chuang-Han Hsu and Kyusup Lee and Yi Wang and Li Yang and Junyong Wang and Qisheng Wang and Hao Wu and Wenfeng Zhang and Goki Eda and Gengchiau Liang and Haixin Chang and Hyunsoo Yang},
doi = {10.1002/qute.202100038},
times_cited = {0},
year = {2021},
date = {2021-06-19},
journal = {ADVANCED QUANTUM TECHNOLOGIES},
volume = {4},
number = {8},
publisher = {WILEY},
address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA},
abstract = {Weyl semimetal Td-phase WTe2 possesses the spin-resolved band structure with strong spin-orbit coupling, holding promises as a useful spin source material. The noncentrosymmetric crystalline structure of Td-WTe2 endows the generation of the out-of-plane polarized spin, which is of great interest in magnetic memory applications. Previously, WTe2 was explored in spin devices based on mechanically exfoliated single crystal flakes with a size of micrometers. For practical spintronics applications, it is highly desirable to implement wafer-scale thin films. In this work, centimeter-scale chemical vapor deposition (CVD) grown Td-WTe2 thin films are used and the spin current generation is studied by the spin torque ferromagnetic resonance (ST-FMR) technique. The in-plane and out-of-plane spin conductivities of 7.36 x 10(3) (PLANCK CONSTANT OVER TWO PI/2e) (ohm m)(-1) and 1.76 x 10(3) (PLANCK CONSTANT OVER TWO PI/2e) (ohm m)(-1), respectively, are found in CVD-growth 5 nm-WTe2. The current-induced magnetization switching in WTe2/NiFe is demonstrated at room temperature in the domain wall motion regime, which may invigorate potential spintronic device innovations based on Weyl semimetals.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:000554472200001,
title = {Spin-Orbit Torque Magnetization Switching in MoTe_{2}/Permalloy Heterostructures},
author = {Shiheng Liang and Shuyuan Shi and Chuang-Han Hsu and Kaiming Cai and Yi Wang and Pan He and Yang Wu and Vitor M Pereira and Hyunsoo Yang},
doi = {10.1002/adma.202002799},
times_cited = {8},
issn = {0935-9648},
year = {2020},
date = {2020-08-02},
journal = {ADVANCED MATERIALS},
volume = {32},
number = {37},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {The ability to switch magnetic elements by spin-orbit-induced torques has recently attracted much attention for a path toward high-performance, nonvolatile memories with low power consumption. Realizing efficient spin-orbit-based switching requires the harnessing of both new materials and novel physics to obtain high charge-to-spin conversion efficiencies, thus making the choice of spin source crucial. Here, the observation of spin-orbit torque switching in bilayers consisting of a semimetallic film of 1T '-MoTe(2)adjacent to permalloy is reported. Deterministic switching is achieved without external magnetic fields at room temperature, and the switching occurs with currents one order of magnitude smaller than those typical in devices using the best-performing heavy metals. The thickness-dependence can be understood if the interfacial spin-orbit contribution is considered in addition to the bulk spin Hall effect. Further threefold reduction in the switching current is demonstrated with resort to dumbbell-shaped magnetic elements. These findings foretell exciting prospects of using MoTe(2)for low-power semimetal-material-based spin devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:000488977100013,
title = {All-electric magnetization switching and Dzyaloshinskii-Moriya interaction in WTe_{2}/ferromagnet heterostructures},
author = {Shuyuan Shi and Shiheng Liang and Zhifeng Zhu and Kaiming Cai and Shawn D Pollard and Yi Wang and Junyong Wang and Qisheng Wang and Pan He and Jiawei Yu and Goki Eda and Gengchiau Liang and Hyunsoo Yang},
doi = {10.1038/s41565-019-0525-8},
times_cited = {0},
issn = {1748-3387},
year = {2019},
date = {2019-10-01},
journal = {NATURE NANOTECHNOLOGY},
volume = {14},
number = {10},
pages = {945-+},
publisher = {NATURE PUBLISHING GROUP},
address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},
abstract = {All-electric magnetization manipulation at low power is a prerequisite for a wide adoption of spintronic devices. Materials such as heavy metals(1-3) or topological insulators(4,5) provide good charge-to-spin conversion efficiencies. They enable magnetization switching in heterostructures with either metallic ferromagnets or with magnetic insulators. Recent work suggests a pronounced Edelstein effect in Weyl semimetals due to their non-trivial band structure(6,7); the Edelstein effect can be one order of magnitude stronger than it is in topological insulators or Rashba systems. Furthermore, the strong intrinsic spin Hall effect from the bulk states in Weyl semimetals can contribute to the spin current generation(8). The Td phase of the Weyl semimetal WTe2 (WTe2 hereafter) possesses strong spin-orbit coupling(6,9) and non-trivial band structures(10) with a large spin polarization protected by time-reversal symmetry in both the surface and bulk states(9-11). Atomically flat surfaces, which can be produced with high quality(12), facilitate spintronic device applications. Here, we use WTe2 as a spin current source in WTe2/Ni81Fe19 (Py) heterostructures. We report field-free current-induced magnetization switching at room temperature. A charge current density of similar to 2.96 x 10(5) A cm(-2) suffices to switch the magnetization of the Py layer. With the charge current along the b axis of the WTe2 layer, the thickness-dependent charge-to-spin conversion efficiency reaches 0.51 at 6-7 GHz. At the WTe2/Py interface, a Dzyaloshinskii-Moriya interaction (DMI) with a DMI constant of -1.78 +/- 0.06 mJ m(-2) induces chiral domain wall tilting. Our study demonstrates the capability of WTe2 to efficiently manipulate magnetization and sheds light on the role of the interface in Weyl semimetal/magnet heterostructures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:000461757900007,
title = {Nonlinear magnetotransport shaped by Fermi surface topology and convexity},
author = {Pan He and Chuang-Han Hsu and Shuyuan Shi and Kaiming Cai and Junyong Wang and Qisheng Wang and Goki Eda and Hsin Lin and Vitor M Pereira and Hyunsoo Yang},
doi = {10.1038/s41467-019-09208-8},
times_cited = {0},
issn = {2041-1723},
year = {2019},
date = {2019-03-20},
journal = {NATURE COMMUNICATIONS},
volume = {10},
publisher = {NATURE RESEARCH},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {The nature of Fermi surface defines the physical properties of conductors and many physical phenomena can be traced to its shape. Although the recent discovery of a current-dependent nonlinear magnetoresistance in spin-polarized non-magnetic materials has attracted considerable attention in spintronics, correlations between this phenomenon and the underlying fermiology remain unexplored. Here, we report the observation of nonlinear magnetoresistance at room temperature in a semimetal WTe2, with an interesting temperature-driven inversion. Theoretical calculations reproduce the nonlinear transport measurements and allow us to attribute the inversion to temperature-induced changes in Fermi surface convexity. We also report a large anisotropy of nonlinear magnetoresistance in WTe2, due to its low symmetry of Fermi surfaces. The good agreement between experiments and theoretical modeling reveals the critical role of Fermi surface topology and convexity on the nonlinear magneto-response. These results lay a new path to explore ramifications of distinct fermiology for nonlinear transport in condensed-matter.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:000414662500005,
title = {Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques},
author = {Yi Wang and Dapeng Zhu and Yang Wu and Yumeng Yang and Jiawei Yu and Rajagopalan Ramaswamy and Rahul Mishra and Shuyuan Shi and Mehrdad Elyasi and Kie-Leong Teo and Yihong Wu and Hyunsoo Yang},
doi = {10.1038/s41467-017-01583-4},
times_cited = {0},
issn = {2041-1723},
year = {2017},
date = {2017-11-08},
journal = {NATURE COMMUNICATIONS},
volume = {8},
publisher = {NATURE PUBLISHING GROUP},
address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND},
abstract = {Topological insulators with spin-momentum-locked topological surface states are expected to exhibit a giant spin-orbit torque in the topological insulator/ferromagnet systems. To date, the topological insulator spin-orbit torque-driven magnetization switching is solely reported in a Cr-doped topological insulator at 1.9 K. Here we directly show giant spin-orbit torque-driven magnetization switching in a Bi2Se3/NiFe heterostructure at room temperature captured using a magneto-optic Kerr effect microscope. We identify a large charge-to-spin conversion efficiency of similar to 1-1.75 in the thin Bi2Se3 films, where the topological surface states are dominant. In addition, we find the current density required for the magnetization switching is extremely low, similar to 6 x 10(5) A cm(-2), which is one to two orders of magnitude smaller than that with heavy metals. Our demonstration of room temperature magnetization switching of a conventional 3d ferromagnet using Bi2Se3 may lead to potential innovations in topological insulator-based spintronic applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}