In-plane magnetic field-driven symmetry breaking in topological insulator-based three-terminal junctions

Topological surface states of three-dimensional topological insulator nanoribbons and their distinct magnetoconductance properties are promising for topoelectronic applications and topological quantum computation. A crucial building block for nanoribbon-based circuits are three-terminal junctions. While the transport of topological surface states on a planar boundary is not directly affected by an in-plane magnetic field, the orbital effect cannot be neglected when the surface states are confined to the boundary of a nanoribbon geometry. Here, we report on the magnetotransport properties of such three-terminal junctions. We observe a dependence of the current on the in-plane magnetic field, with a distinct steering pattern of the surface state current towards a preferred output terminal for different magnetic field orientations. We demonstrate that this steering effect originates from the orbital effect, trapping the phase-coherent surface states in the different legs of the junction on opposite sides of the nanoribbon and breaking the left-right symmetry of the transmission across the junction. The reported magnetotransport properties demonstrate that an in-plane magnetic field is not only relevant but also very useful for the characterization and manipulation of transport in three-dimensional topological insulator nanoribbon-based junctions and circuits, acting as a topoelectric current switch.

Orbital Effect on Carbyne Based Sensor

Carbyne material with sp-hybridized atoms has been considered as a one dimensional structure with unique properties which has been widely used in nanotechnology. In the presented work the effect of electron overlap energy in the form of electron interaction with in the unit cell and nearest neighbors is explored. In addition, the band structure variation under proposed interaction in one dimensional carbyne is investigated. The effect of overlap energy variation inside and outside the unit cell on the band gap is intended. Under proposed structure the effective mass and density of states parameters are explored. It is demonstrated that by increasing the interaction between s and p orbitals in the unit cell, the band gap increases. However, the band gap is decreased by increasing the interaction between s and p orbitals out the unit cell which can be sued as a sensing mechanism.