Quantized conductance and field-effect topological quantum transistor in silicene nanoribbons

Abstract

Silicene (a monolayer of silicon atoms) is a quantum spin-Hall insulator, which undergoes a topological phase transition into other insulators by applying external field such as electric field, photo-irradiation and antiferromagnetic order. We investigate the electronic and transport properties of silicene nanoribbons based on the Landauer formalism. We propose to determine topological phase transitions by measuring the density of states and conductance. The conductance is quantized and changes its value when the system transforms into different phases. We show that a silicene nanoribbon near the zero energy acts as a field-effect transistor. This transistor is robust though it makes use of the minimum quantized conductance since the zero-energy edge states are topologically protected. Our findings open a new way to future topological quantum devices.

Silicene on Ag(111): Geometric and electronic structures of a new honeycomb material of Si

“…The external electric field breaks the inversion symmetry to enhance spin-orbit coupling through the Rashba effect. Various novel properties of silicene derived from the topological nature have been explored theoretically [36][37][38][39][40][41][42][43][44][45][46][47][48].…”

Giant magnetoresistance and perfect spin filter in silicene, germanene, and stanene

“…One might call this setup also a topological quantum transistor 35 since the conductance can be switched by the external field.…”

Can a silicene transistor be realized?

“…Despite the fact that there is still a long way to go several recent articles have provided a tantalizing hint of the possibility of silicene or silicene nanoribbon-based field effect transistors [40,[43][44][45][46]. As silicene offers the prospect of compatibility with the existing silicon technology, it is in the forefront of novel materials with a potential for future applications.…”