Identification and tunable optical coherent control of transition-metal spins in silicon carbide

Tom Bosma,Björn Magnusson,N T Son,Remco W A Havenith,Carmem M Gilardoni,Ivan G Ivanov,Caspar H Van Der Wal,Gerrit J J Lof,Freddie Hendriks,Olger V Zwier,Andreas Gällström,Alexandre Ellison

doi:10.1038/s41534-018-0097-8

Abstract

Color centers in wide-bandgap semiconductors are attractive systems for quantum technologies since they can combine long-coherent electronic spin and bright optical properties. Several suitable centers have been identified, most famously the nitrogen-vacancy defect in diamond. However, integration in communication technology is hindered by the fact that their optical transitions lie outside telecom wavelength bands. Several transition-metal impurities in silicon carbide do emit at and near telecom wavelengths, but knowledge about their spin and optical properties is incomplete. We present all-optical identification and coherent control of molybdenum-impurity spins in silicon carbide with transitions at near-infrared wavelengths. Our results identify spin S = 1/2 for both the electronic ground and excited state, with highly anisotropic spin properties that we apply for implementing optical control of ground-state spin coherence. Our results show optical lifetimes of ~60 ns and inhomogeneous spin dephasing times of ~0.3 μs, establishing relevance for quantum spin-photon interfacing.

Highlights

Electronic spins of lattice defects in wide-bandgap semiconductors have come forward as an important platform for quantum technologies,[1] in particular for applications that require both manipulation of long-coherent spin and spin-photon interfacing via bright optical transitions
In order to study the occurrence of coherent population trapping (CPT), we focus on the twolaser photoluminescence excitation (PLE) features that result from a Λ scheme
In these cases the transition metal has a single electron in its 3d orbital and occupies the hexagonal (h) Si substitutional site

Summary

INTRODUCTION

Electronic spins of lattice defects in wide-bandgap semiconductors have come forward as an important platform for quantum technologies,[1] in particular for applications that require both manipulation of long-coherent spin and spin-photon interfacing via bright optical transitions. Using a two-laser magneto-spectroscopy method,[28,43,44] we identify the spin Hamiltonian of the S = 1/2 ground state and optically excited state, which behave as doublets with highly anisotropic Landé g-factors This gives insight in how a situation with only spin-conserving transitions can be broken, and we find that we can use a weak magnetic field to enable optical in the 4H-SiC sample, together with a study of the temperature dependence of the PL, can be found in Supplementary Information (Fig. S1). The two-laser detuning frequencies for the pumping schemes in Fig. 3a–d are related in the same way, which justifies the assignment of these four schemes to the emission lines L1 through L4, respectively These schemes and equations directly yield the g-factor values gg and ge for the ground and excited state (Supplementary Information section 2). EPR studies by Baur et al.[33] on various transition-metal impurities show that the inhomogeneity probably has a strong static

DISCUSSION

METHODS