Magnetoelectric transport properties in topological nodal-line semimetals

Abstract

We study the impact of the size effect and the varying perpendicular magnetic field B on the transport properties of topological nodal-line semimetals (TNLSMs) by using the Landauer–Büttiker formula combined with the nonequilibrium Green’s function. We theoretically calculate the band structure, conductance G and local density of states (LDOS) of TNLSMs nanowire. The results show that both the size effect and the application of varying magnetic field play a crucial role in the electron transport of TNLSMs. We find that both the step height and width of the conductance plateau in TNLSMs are closely related to the size effect of the system. For the system with a large TNLSMs, the low energy states are dominated by flat bands, leading to a series of quantized conductance plateaus. Furthermore, it has been observed that the presence of a magnetic field leads to the formation of the Landau levels in the TNLSMs, which exhibit sensitivity to the direction of the applied magnetic field. A perpendicular magnetic field parallel to the transport direction forms a linearly dispersed Landau level in the TNLSMs system, which leads to an increase in its conductance G and LDOS. At the same time, when the magnetic field perpendicular to the transport direction is applied, a series of the Landau levels with the flat bands are formed near the Fermi energy level EF of the system, resulting in a significant decrease of its conductance G and a rapid decay of LDOS. These unique physical properties of the TNLSMs nanowire offer a wide range of the applications in magnetoelectric transport.

Keywords

• Magnetoelectric transport
• Size effect
• Topological nodal-line semimetals
• Nonequilibrium Green’s function method