Two-dimensional Cu 2 Si sheet: a promising electrode material for nanoscale electronics.

Building electronic devices on top of two-dimensional (2D) materials has recently become one of most interesting topics in nanoelectronics. Finding high-performance 2D electrode materials is one central issue in 2D nanoelectronics. In the current study, based on first-principles calculations, we compare the electronic and transport properties of two nanoscale devices. One device consists of two single-atom-thick planar Cu2 Si electrodes, and a nickel phthalocyanine (NiPc) molecule in the middle. The other device is made of often-used graphene electrodes and a NiPc molecule. Planer Cu2 Si is a new type of 2D material that was recently predicted to exist and be stable under room temperature [11]. We found that at low bias voltages, the electric current through the Cu2 Si-NiPc-Cu2 Si junction is about three orders higher than that through graphene-NiPc-graphene. Detailed analysis shows that the surprisingly high conductivity of Cu2 Si-NiPc-Cu2 Si originates from the mixing of the Cu2 Si state near Fermi energy and the highest occupied molecular orbital of NiPc. These results suggest that 2D Cu2 Si may be an excellent candidate for electrode materials for future nanoscale devices.