Yawen Liu

Above 400-K robust perpendicular ferromagnetic phase in a topological insulator

Topological surface states reveal proximity-induced ferromagnetism with perpendicular anisotropy persisting above 400 K. The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TIs) exhibits many fascinating physical properties for potential applications in nanoelectronics and spintronics. However, in transition metal–doped TIs, the only experimentally demonstrated QAHE system to date, the QAHE is lost at practically relevant temperatures. This constraint is imposed by the relatively low Curie temperature (Tc) and inherent spin disorder associated with the random magnetic dopants. We demonstrate drastically enhanced Tc by exchange coupling TIs to Tm3Fe5O12, a high-Tc magnetic insulator with perpendicular magnetic anisotropy. Signatures showing that the TI surface states acquire robust ferromagnetism are revealed by distinct squared anomalous Hall hysteresis loops at 400 K. Point-contact Andreev reflection spectroscopy confirms that the TI surface is spin-polarized. The greatly enhanced Tc, absence of spin disorder, and perpendicular anisotropy are all essential to the occurrence of the QAHE at high temperatures.

Strong electron-hole symmetric Rashba spin-orbit coupling in graphene/monolayer transition metal dichalcogenide heterostructures

Despite its extremely weak intrinsic spin-orbit coupling (SOC), graphene has been shown to acquire considerable SOC by proximity coupling with exfoliated transition metal dichalcogenides (TMDs). Here we demonstrate strong induced Rashba SOC in graphene that is proximity coupled to a monolayer TMD film,

Deficiency of the bulk spin Hall effect model for spin-orbit torques in magnetic-insulator/heavy-metal heterostructures

\mathrm{Mo}{\mathrm{S}}_{2}

Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature

or

Role of dimensional crossover on spin-orbit torque efficiency in magnetic insulator thin films

\mathrm{WS}{\mathrm{e}}_{2}

Anomalous Hall hysteresis in T m 3 F e 5 O 12 / Pt with strain-induced perpendicular magnetic anisotropy

, grown by chemical-vapor deposition with drastically different Fermi level positions. Graphene/TMD heterostructures are fabricated with a pickup-transfer technique utilizing hexagonal boron nitride, which serves as a flat template to promote intimate contact and therefore a strong interfacial interaction between TMD and graphene as evidenced by quenching of the TMD photoluminescence. We observe strong induced graphene SOC that manifests itself in a pronounced weak-antilocalization (WAL) effect in the graphene magnetoconductance. The spin-relaxation rate extracted from the WAL analysis varies linearly with the momentum scattering time and is independent of the carrier type. This indicates a dominantly Dyakonov-Perel spin-relaxation mechanism caused by the induced Rashba SOC. Our analysis yields a Rashba SOC energy of \ensuremath{\sim}1.5 meV in graphene/

Anomalous Hall hysteresis inTm3Fe5O12/Ptwith strain-induced perpendicular magnetic anisotropy

\mathrm{WS}{\mathrm{e}}_{2}

Dirac-Surface-State Modulated Spin Dynamics in a Ferrimagnetic Insulator at Room Temperature

and \ensuremath{\sim}0.9 meV in graphene/

Strain induced perpendicular magnetic anisotropy in epitaxial europium iron garnet thin films

\mathrm{Mo}{\mathrm{S}}_{2}

Length scale of spin-orbit torques and efficient switching in magnetic insulators

. The nearly electron-hole symmetric nature of the induced Rashba SOC provides a clue to possible underlying SOC mechanisms.