Air-stable van der Waals PtTe2 conductors with high current-carrying capacity and strong spin- orbit interaction

High-performance van der Waals (vdW) integrated electronics and spintronics require reliable current-carrying capacity. However, it is challenging to achieve high current density and air-stable performance using vdW metals owing to the fast electrical breakdown triggered by defects or oxidation. Here, we report that spin-orbit interacted synthetic PtTe2 layers exhibit significant electrical reliability and robustness in ambient air. The 4-nm-thick PtTe2 synthesized at a low temperature (similar to 400 degrees C) shows intrinsic metallic transport behavior and a weak antilocalization effect attributed to the strong spin-orbit scattering. Remarkably, PtTe2 sustains a high current density approaching approximate to 31.5 MA cm(-2), which is the highest value among electrical interconnect candidates under oxygen exposure. Electrical failure is caused by the Joule heating of PtTe2 rather than defect-induced electromigration, which was achievable by the native TeOx passivation. The high-quality growth of PtTe2 and the investigation of its transport behaviors lay out essential foundations for the development of emerging vdW spin-orbitronics

A scalable molecule-based magnetic thin film for spin-thermoelectric energy conversion

Spin thermoelectrics, an emerging thermoelectric technology, offers energy harvesting from waste heat with potential advantages of scalability and energy conversion efficiency, thanks to orthogonal paths for heat and charge flow. However, magnetic insulators previously used for spin thermoelectrics pose challenges for scale-up due to high temperature processing and difficulty in large-area deposition. Here, we introduce a molecule-based magnetic film for spin thermoelectric applications because it entails versatile synthetic routes in addition to weak spin-lattice interaction and low thermal conductivity. Thin films of Cr-II[Cr-III(CN)(6)], Prussian blue analogue, electrochemically deposited on Cr electrodes at room temperature show effective spin thermoelectricity. Moreover, the ferromagnetic resonance studies exhibit an extremely low Gilbert damping constant -(2.4 +/- 0.67) x10(-4), indicating low loss of heat-generated magnons. The demonstrated STE applications of a new class of magnet will pave the way for versatile recycling of ubiquitous waste heat

Gate-dependent spin Hall induced nonlocal resistance and the symmetry of spin-orbit scattering in Au-clustered graphene

Engineering the electron dispersion of graphene to be spin-dependent is crucial for the realization of spin-based logic devices. Enhancing spin-orbit coupling in graphene can induce spin Hall effect, which can be adapted to generate or detect a spin current without a ferromagnet. Recently, both chemically and physically decorated graphenes have shown to exhibit large nonlocal resistance via the spin Hall and its inverse effects. However, these nonlocal transport results have raised critical debates due to the absence of field dependent Hanle curve in subsequent studies. Here, we introduce Au clusters on graphene to enhance spin-orbit coupling and employ a nonlocal geometry to study the spin Hall induced nonlocal resistance. Our results show that the nonlocal resistance highly depends on the applied gate voltage due to various current channels. However, the spin Hall induced nonlocal resistance becomes dominant at a particular carrier concentration, which is further confirmed through Hanle curves. The obtained spin Hall angle is as high as similar to 0.09 at 2 K. Temperature dependence of spin relaxation time is governed by the symmetry of spin-orbit coupling, which also depends on the gate voltage: asymmetric near the charge neutral point and symmetric at high carrier concentration. These results inspire an effective method for generating spin currents in graphene and provide important insights for the spin Hall effect as well as the symmetry of spin scattering in physically decorated graphene

Spin thermoelectric energy conversion based-on hybrid magnetic insulator

Department of Materials Science and Engineeringclos

Correlation between a Structural Change and a Thermoelectric Performance of a Glassy Carbon Thin Film Induced by Electron Beam Irradiation

Glassy carbon can be utilized in a variety of harsh environment due to exceptional thermal stability and chemically impermeability along with scalability and low electrical resistance. In this work, we studied effects of electron(e)-beam irradiation on thermoelectric properties of the glassy carbon film. E-beam irradiation triggered local crystallization and/or amorphization of glassy carbon thin films, which was determined by a Raman spectroscopy. The structural change by e-beam irradiation leads to the change in the doping level of the glassy carbon, which can be inferred from the change of a Seebeck coefficient and an electric conductivity. The optimal power factor we obtained for the irradiated glassy carbon film was ~200% higher than that of the non-irradiated sample.clos

Local crystallization and enhanced thermoelectric performance of glassy carbon induced by the electron beam irradiation

Glassy carbon can be used in a variety of harsh environments because it exhibits low electrical resistance, high thermal stability, chemically impermeability and hardness. In this work, we studied the potential application of the pyrolized glassy carbon as a thermoelectric material by electron beam irradiation. Irradiation with electron beam energy of 1.4 MeV and 0.2 MeV triggered local crystallization of glassy carbon, which was determined by a Raman spectroscopy. As the irradiation time was increased, the number of sp2 hybridized carbons was gradually increased while the number of disordered carbons was decreased. This electron beam induced local crystallization caused a synergetic effect on a thermoelectric power factor of the studied glassy carbon films. Although the electrical conductivity was decreased by the e-beam irradiation, the Seebeck coefficient was significantly enhanced resulting in an improved power factor. The optimal power factor we obtained for the irradiated glassy carbon was ???50% higher than that of the non-irradiated sample.clos