Proximity spin-orbit coupling in an armchair carbon nanotube on monolayer bismuthene

TL;DR

This paper investigates how a monolayer bismuthene induces strong spin-orbit coupling in an armchair carbon nanotube through proximity effects, with results supported by first-principles calculations and an effective Hamiltonian.

Contribution

It demonstrates the enhancement of spin-orbit coupling in nanotubes via proximity to bismuthene and formulates an effective model for this interaction.

Findings

Large spin-orbit coupling induced in nanotubes

Dependence of band structure on nanotube position

Proximity-induced spin splitting in meV range

Abstract

We study spin-orbit proximity effects in a hybrid heterostructure build of a one-dimensional (1D) armchair carbon nanotube and two-dimensional (2D) buckled monolayer bismuthene. We show, by performing first-principles calculations, that Dirac electrons in the nanotube exhibit large spin-orbit coupling due to a close vicinity of bismuthene. The calculated low-energy band structures of the proximized nanotube display a strong dependence on the position of the nanotube on the substrate, similar to twist-angle dependence found in 2D heterostructures. Based on the first-principles results, we formulate an effective low-energy Hamiltonian of the nanotube and identify key interactions governing the proximity spin-orbit coupling. The proximity-induced spin splitting of Dirac cone bands is in meV range, confirming an efficient transfer of spin-orbit coupling from bismuthene to the nanotube.