Quantum interference and contact effects in dangling bond loops on H-Si(100) surfaces

TL;DR

This study investigates quantum interference effects in dangling bond loops on H-Si(100) surfaces, demonstrating how loop length and contact position significantly influence electron transport, enabling potential nanocircuit engineering.

Contribution

It introduces a density-functional based tight-binding approach to model and analyze quantum interference in dangling bond loops on silicon surfaces.

Findings

Transport properties vary by orders of magnitude with interference effects.

Loop length and contact position critically affect electron transmission.

Constructive and destructive interference can be engineered for desired conductance.

Abstract

We perform electronic structure and quantum transport studies of dangling bond loops created on H-passivated Si(100) surfaces and connected to carbon nanoribbon leads. We model loops with straight and zigzag topologies as well as with varying lenght with an efficient density-functional based tight-binding electronic structure approach (DFTB) . Varying the length of the loop or the lead coupling position we induce the drastic change in the transmission due to the electron interference. Depending if the constructive or destructive interference within the loop takes place we can noticeably change transport properties by few orders of magnitude. These results propose a way to engineer the closed electronically driven nanocircuits with high transport properties and exploit the interference effects in order to control them.