Search

Using density functional theory and nonequilibrium Green's function method, we investigated the spin-dependent transport and spin-polarized optoelectronic properties of the 6,6,12-graphyne-based magnetic tunnel junction (MTJ) devices. The results show that the MTJ devices have prominent dual spin-filtering effect and large tunneling magnetoresistance (TMR); the TMR values of the MTJ devices are as high as 105%. In addition, we found that the spin-polarized photocurrents of the MTJ devices are dependent on the polarization direction of light and the magnetization directions of the electrodes. Two spin-polarized photocurrents can be realized in the MTJ devices and, if the magnetization directions of the two electrodes are antiparallel, the two light-generated spins flow in opposite directions. These interesting phenomena indicate that the 6,6,12-graphyne-based MTJ devices could be used as optoelectronic or opto-spintronic devices.

The promised performance of monolayer molybdenum disulfide (MoS2)-based devices is hindered by the high electrical resistance at the metal-MoS2 contact. Benefitting from the metallic phase of MoS2, 1T-MoS2 is considered a potential electrode material for the semiconducting 2H-MoS2. In this paper, we report a comparative study of the allotropic 1T/2H MoS2 contact with different contact types. The edge-contact interface has a low tunnel barrier, high charge density, and even Ohmic contact with no Schottky barrier, which implies that this contact may overcome the resistance limit for the electrode-MoS2 contact. The outstanding interface properties of the 1T/2H MoS2 edge contact originate from the excess in-plane dangling bonds in the edge position. Based on our results, the edge-contact model is ideal for the 1T/2H MoS2 contact and may solve the problem of MoS2 contact resistance.

We investigated the upper critical fields of Ca10(Pt4As8)(Fe2–xPtxAs2)5 superconducting whiskers. The whiskers consist of several wire-like grains with diameter of around 200 nm, joined by grain boundaries whose misorientation angles are less than 5∘. The upper critical fields along c-axis and in ab-plane were observed as 49 T at 12 K and 50 T at 22 K, respectively, which can be extrapolated to ∼81 and ∼133 T at 0 K. The whisker demonstrated weak anisotropic factor and almost constant value of ∼2 below 15 K. The impressive transport properties of the whisker may find applications in fields like superconducting micro- and meso-structure systems.