Spin-dependent vibronic response of a carbon radical ion in two-dimensional WS2

Katherine A Cochrane,Tianyi Zhang,Joshua A Robinson,Jeffrey B Neaton,Mauricio Terrones,Bruno Schuler,Jun-Ho Lee,Jonah B Haber,Alexander Weber-Bargioni,Jascha Repp,Azimkhan Kozhakhmetov,Christoph Kastl

doi:10.1038/s41467-021-27585-x

Abstract

Atomic spin centers in 2D materials are a highly anticipated building block for quantum technologies. Here, we demonstrate the creation of an effective spin-1/2 system via the atomically controlled generation of magnetic carbon radical ions (CRIs) in synthetic two-dimensional transition metal dichalcogenides. Hydrogenated carbon impurities located at chalcogen sites introduced by chemical doping are activated with atomic precision by hydrogen depassivation using a scanning probe tip. In its anionic state, the carbon impurity is computed to have a magnetic moment of 1 μB resulting from an unpaired electron populating a spin-polarized in-gap orbital. We show that the CRI defect states couple to a small number of local vibrational modes. The vibronic coupling strength critically depends on the spin state and differs for monolayer and bilayer WS2. The carbon radical ion is a surface-bound atomic defect that can be selectively introduced, features a well-understood vibronic spectrum, and is charge state controlled.

Highlights

Atomic spin centers in 2D materials are a highly anticipated building block for quantum technologies
We demonstrate that the electron-phonon coupling associated with the two discrete electronic carbon radical ions (CRIs) defect states is limited to a only few vibrational modes and exhibits a distinct spin and layer dependence
In the following, we discuss our three primary conclusions: the hydrogen depassivation of the CH impurity and formation of the CRI, the two spin-polarized defect states associated with the CRI, and the vibronic coupling of the CRI defect states with the transition metal dichalcogenides (TMDs) host lattice

Summary

Introduction

Atomic spin centers in 2D materials are a highly anticipated building block for quantum technologies. We precisely characterize the coupling of the spin-polarized local defect states generated by the CRI with its host lattice. We demonstrate that the electron-phonon coupling associated with the two discrete electronic CRI defect states is limited to a only few vibrational modes and exhibits a distinct spin and layer dependence.

Results

Conclusion