Valley filter in strain engineered graphene

We propose a simple, yet highly efficient and robust device for producing valley polarized current in graphene. The device comprises of two distinct components; a region of uniform uniaxial strain, adjacent to an out-of-plane magnetic barrier configuration formed by patterned ferromagnetic gates. We show that when the amount of strain, magnetic field strength, and Fermi level are properly tuned, the output current can be made to consist of only a single valley contribution. Perfect valley filtering is achievable within experimentally accessible parameters.Comment: 4 pages, 3 figures; minor corrections, updated Figs. 2 and 3, added reference

Spin force and intrinsic spin Hall effect in spintronics systems

We investigate the spin Hall effect (SHE) in a wide class of spin-orbit coupling systems by using spin force picture. We derive the general relation equation between spin force and spin current and show that the longitudinal force component can induce a spin Hall current, from which we reproduce the spin Hall conductivity obtained previously using Kubo's formula. This simple spin force picture gives a clear and intuitive explanation for SHE

Sistem Kontrol Mesin Penukaran Uang Kertas Rupiah Berbasis Pengolahan Citra dan Raspberry Pi

The research purpose is to build a machine control system for exchange nominal of rupiah's paper money from big nominal to small nominal based on image processing and Raspberry Pi. The method for money exchange is detecting the authenticity of money, nominal of money, and amount of money exchange. The money authenticity was detected by the invisible image and nominal of money was detected by money color. Technique for detection the authenticity and nominal of money are using image processing that is processed on the Raspberry Pi. The algorithm used for detecting the authenticity and nominal of money are using template color algorithm and for exchange amount of money using the greedy algorithm. The research result is system able to detect the authenticity and nominal of paper money IDR 100.000, IDR 50.000, and IDR 20.000 then exchange it with the small nominal of money in accordance with the user choice