All‐Electric Spin Device Operation Using the Weyl Semimetal, WTe₂, at Room Temperature

Abstract

Topological quantum materials (TQMs) possess abundant and attractive spin physics, and a Weyl semimetal is the representative material because of the generation of spin polarization that is available for spin devices due to its Weyl nature. Meanwhile, a Weyl semimetal allows the other but unexplored spin polarization due to local symmetry breaking. Here, all‐electric spin device operation using a type‐II Weyl semimetal, WTe2, at room temperature is reported. The polarization of spins propagating in the all‐electric device is perpendicular to the WTe2 plane, which is ascribed to local in‐plane symmetry breaking in WTe2, yielding the spin polarization creation of propagating charged carriers, namely, the spin‐polarized state creation from the nonpolarized state. Systematic control experiments unequivocally negate unexpected artifacts, such as the anomalous Hall effect, the anisotropic magnetoresistance, etc. Creation of all‐electric spin devices made of TQMs and their operation at room temperature can pave a new pathway for novel spin devices made of TQMs resilient to thermal fluctuation.

Topological quantum devices: a review

“…With strong SOC and broken inversion symmetry, exotic spin textures enable a large spin Hall effect that can efficiently convert the charge into spin current in a type-II WTe 2 Weyl semimetal. 199,200 While both Dirac and Weyl devices share similarities in terms of their topological nature, their distinct band structures and associated phenomena provide different applications. There is also another interesting field that uses non-Hermitian topological systems as novel high-precision sensors.…”

Research on Spintronic Functions of Non-Metallic Materials and Its Modulation by External Fields

“…In the case when a FM material is used as a detector electrode, R ISHE can be written in terms of the conventional fluctuation and spin signals are detectable up to RT 67) , which enables creation of all-electric spin devices using a Weyl semimetal (Fig. 10).…”

Wafer-Scale Synthesis of Highly Oriented 2D Topological Semimetal PtTe2 via Tellurization

“…1,2 After Dirac/Weyl Fermions in 2D semimetals have been theoretically predicted and experimentally confirmed, 3−15 the investigation into utilizing Dirac/Weyl Fermions or nontrivial topological states for the development of future electronic and spintronic devices has been initiated. For example, the gapless band structure is promising for infrared detectors with a high sensitivity response over a wide spectral band with vdW integration, 16−20 and the topological surface states with spin-momentum locking are suitable for spintronics such as high quantum Hall conductive devices having a sharp interface, 21,22 and the topological superconductivity can be utilized as a fault-tolerant qubit for future quantum computa-tions. 23−25 However, the limitation of these demonstrations is that the observation of topological electronic band structures was conducted using small-sized single crystals, or device applications were demonstrated using polycrystalline thin films.…”

“…Two-dimensional (2D) topological semimetals are interesting material systems with extraordinary physical properties originating from electronic band topology and great flexibility to synthesize heterostructures through the weak van der Waals (vdW) structures, offering a low-energy materials integration approach. , After Dirac/Weyl Fermions in 2D semimetals have been theoretically predicted and experimentally confirmed, − the investigation into utilizing Dirac/Weyl Fermions or nontrivial topological states for the development of future electronic and spintronic devices has been initiated. For example, the gapless band structure is promising for infrared detectors with a high sensitivity response over a wide spectral band with vdW integration, − and the topological surface states with spin-momentum locking are suitable for spintronics such as high quantum Hall conductive devices having a sharp interface, , and the topological superconductivity can be utilized as a fault-tolerant qubit for future quantum computations. − However, the limitation of these demonstrations is that the observation of topological electronic band structures was conducted using small-sized single crystals, or device applications were demonstrated using polycrystalline thin films. Unfortunately, such thin films cannot fully deserve the crystallographic anisotropy and theoretically expected topological properties due to the randomness of the in-plane orientation with a large number of dislocations.…”