Orbitally resolved single-photon emission from an individual atomic vacancy center in a semiconductor
Nanyang Technological University（南洋理工大学）
Gagandeep Singh, Xiaodan Lyu, Bi Qi Chong, Ryan Li Yen Tang, Rejaul SK, Yande Que, Ranjith Shivajirao, Thasneem Aliyar, Radha Krishnan, Junxiang Jia, Michael S.… 展开作者
Gagandeep Singh, Xiaodan Lyu, Bi Qi Chong, Ryan Li Yen Tang, Rejaul SK, Yande Que, Ranjith Shivajirao, Thasneem Aliyar, Radha Krishnan, Junxiang Jia, Michael S. Fuhrer, Teck Seng Koh, Weibo Gao, Bent Weber
Atomically confined spins are emerging as active components in quantum optoelectronic devices such as quantum bits and sensors. However, interrogating single spins at atomic length-scales remains a sizeable challenge, limited by diffraction in conventional optics. Here we show that the highly-local excitation provided by injecting energetic charge carriers from the atomically sharp probe of a scanning tunneling microscope can trigger single-photon emission from individual atomic vacancy centers in a layered semiconductor. With an effective spatial resolution of <1 nm, we show that the captured light closely mirrors the orbital symmetry of the bound-state wavefunction of the vacancy center while photon correlation measurements confirm single-photon emission, as reflected in clear photon anti-bunching signatures. Our results constitute an important step toward the realization of an electrically addressable single-atom quantum light source and solid-state spinphoton interface, addressed at the atomic-scale.
We propose a protocol to dissipatively cool a room temperature mechanical resonator using a nitrogen-vacancy (NV) center ensemble. The spin ensemble is coupled to the resonator through its orbitally-averaged excited state, which has a spin-strain interaction that has not been previously characterized. We experimentally demonstrate that the spin-strain coupling in the excited state is $13.5\pm0.5$ times stronger than the ground state spin-strain coupling. We then theoretically show that this interaction combined with a high-density spin ensemble enables the cooling of a mechanical resonator fro…
Nuclear spins in semiconductors are leading candidates for quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their extremely long coherence lifetime. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which has enabled entanglement mediated by photonic links. The transport of quantum information by the electron itself, via controlled transfer to an adjacent centre or via the dipolar interaction, would enable even faster and smaller processors, but optic…
The development of novel quantum bits is key to extend the scope of solid-state quantum information science and technology. Using first-principles calculations, we propose that large metal ion - vacancy complexes are promising qubit candidates in two binary crystals: 4H-SiC and w-AlN. In particular, we found that the formation of neutral Hf- and Zr-vacancy complexes is energetically favorable in both solids; these defects have spin-triplet ground states, with electronic structures similar to those of the diamond NV center and the SiC di-vacancy. Interestingly, they exhibit different spin-strai…
We describe an all-optical scheme for spin manipulation in the ground-state triplet of the negatively charged nitrogen-vacancy (NV) center in diamond. Virtual optical excitation from the 3A_2 ground state into the 3E excited state allows for spin rotations by virtue of the spin-spin interaction in the two-fold orbitally degenerate excited state. We derive an effective Hamiltonian for optically induced spin-flip transitions within the ground state spin triplet due to off-resonant optical pumping. Furthermore, we investigate the spin qubit formed by the Zeeman sub-levels with spin projection m_S…
Optically interfaced spins in the solid promise scalable quantum networks. Robust and reliable optical properties have so far been restricted to systems with inversion symmetry. Here, we release this stringent constraint by demonstrating outstanding optical and spin properties of single silicon vacancy centres in silicon carbide. Despite the lack of inversion symmetry, the system's particular wave function symmetry decouples its optical properties from magnetic and electric fields, as well as from local strain. This provides a high-fidelity spin-to-photon interface with exceptionally stable an…
Point defects in wide-bandgap semiconductors are emerging as versatile resources for nanoscale sensing and quantum information science but our understanding of the photo-ionization dynamics is presently incomplete. Here we use two-color confocal microscopy to investigate the dynamics of charge in Type 1b diamond hosting nitrogen-vacancy (NV) and silicon-vacancy (SiV) centers. By examining the non-local fluorescence patterns emerging from local laser excitation, we show that in the simultaneous presence of photo-generated electrons and holes, SiV (NV) centers selectively transform into the nega…
Quantum localization via atomic point defects in semiconductors is of significant fundamental and technological importance. Quantum defects in monolayer transition-metal dichalcogenide semiconductors have been proposed as stable and scalable optically-addressable spin qubits. Yet, the impact of strong spin-orbit coupling on their dynamical response, for example under optical excitation, has remained elusive. In this context, we study the effect of spin-orbit coupling on the electron-phonon interaction in a single chalcogen vacancy defect in monolayer transition metal dichalcogenides, molybdenu…
Single-photon emitting point defects in semiconductors have emerged as strong candidates for future quantum technology devices. In the present work, we exploit crystalline particles to investigate relevant defect localizations, emission shifting and waveguiding. Specifically, emission from 6H-SiC micro- and nanoparticles ranging from 100 nm to 5 $μ$m in size is collected using cathodoluminescence (CL), and we monitor signals attributed to the Si vacancy (V$_{\textrm{Si}}$) as a function of its location. Clear shifts in the emission wavelength are found for emitters localized in the particle ce…
The structural, electronic, and magnetic properties of pristine, defective, and oxidized monolayer TiS3 are investigated using first-principles calculations in the framework of density functional theory. We found that a single layer of TiS3 is a direct band gap semiconductor, and the bonding nature of the crystal is fundamentally different from other transition metal chalcogenides. The negatively charged surfaces of single layer TiS3 makes this crystal a promising material for lubrication applications. The formation energies of possible vacancies, i.e. S, Ti, TiS, and double S, are investigate…
Nitrogen-vacancy (NV) centers in diamond work as a quantum electrometer. Using an ensemble state of NV centers, we propose vector electrometry and demonstrate measurements in a diamond electronic device. A transverse electric field applied to the N-V axis under a high voltage was measured while applying a transverse magnetic field. The response of the energy level shift against the electric field was significantly enhanced compared with that against an axial magnetic field. Repeating the measurement of the transverse electric field for multiple N-V axes, we obtained the components of the elect…
The influence of atomic vacancy defects at different concentrations on electronic properties of MoS$_2$ and WS$_2$ monolayers is studied by means of Slater-Koster tight-binding model with non-orthogonal $sp^3d^5$ orbitals and including the spin-orbit coupling. The presence of vacancy defects induces localized states in the bandgap of pristine MoS$_2$ and WS$_2$, which have potential to modify the electronic structure of the systems, depending on the type and concentration of the defects. It is shown that although the contribution of metal (Mo or W) $d$ orbitals is dominant in the formation of …
In this work, we have examined how the multi-vacancy defects induced in the horizontal direction change the energetics and the electronic structure of semiconducting Single-Walled Carbon Nanotubes (SWCNTs). The electronic structure of SWCNTs is computed for each deformed configuration by means of real space, Order(N) Tight Binding Molecular Dynamic (O(N) TBMD) simulations. Energy band gap is obtained in real space through the behavior of electronic density of states (eDOS) near the Fermi level. Vacancies can effectively change the energetics and hence the electronic structure of SWCNTs. In thi…
Paramagnetic defects and nuclear spins are often the major sources of decoherence and spin relaxation in solid-state qubits realized by optically addressable point defect spins in semiconductors. It is commonly accepted that a high degree of depletion of nuclear spins can enhance the coherence time by reducing magnetic noise. Here we show that the isotope purification beyond a certain optimal level becomes contra-productive, when both electron and nuclear spins are present in the vicinity of the qubits. Using state-of-the-art numerical tools and considering the silicon vacancy qubit in various…
The detection of photocurrents is central to understanding and harnessing the interaction of light with matter. Although widely used, transport-based detection averages over spatial distributions and can suffer from low photocarrier collection efficiency. Here, we introduce a contact-free method to spatially resolve local photocurrent densities using a proximal quantum magnetometer. We interface monolayer MoS2 with a near-surface ensemble of nitrogen-vacancy centers in diamond and map the generated photothermal current distribution through its magnetic field profile. By synchronizing the photo…
Half-metals and spin gapless semiconductors are promising candidates for spintronic applications due to the complete (100%) spin polarization of electrons around the Fermi level. Based on recent experimental and theoretical findings of graphene-like monolayer transition metal carbides and nitrides (also known as MXenes), we demonstrate from first-principles calculations that monolayer Ti2C and Ti2N exhibit nearly half-metallic ferromagnetism with the magnetic moments of 1.91 and 1.00 UB per formula unit, respectively, while monolayer V2C is a metal with instable antiferromagnetism, and monolay…
Control over the charge states of color centers in solids is necessary in order to fully utilize them in quantum technologies. However, the microscopic charge dynamics of deep defects in wide-bandgap semiconductors are complex, and much remains unknown. Here, we utilize single shot charge state readout of an individual nitrogen-vacancy (NV) center to probe charge dynamics of the surrounding defects in diamond. We show that the NV center charge state can be converted through the capture of holes produced by optical illumination of defects many microns away. With this method, we study the optica…
We present and analyze a hybrid quantum system that interfaces a Majorana-hosted semiconductor nanowire with a single nitrogen-vacancy (NV) center via a magnetized torsional cantilever. We show that, the torsional mode of the mechanical resonator can strongly couple to the Majorana qubit and the spin qubit simultaneously, which allows to interface them for quantum state conversion through a dark state protocol. This work provides a promising interface between the topological qubit and the conventional spin qubit, and can find interesting applications in quantum information and computation.
We demonstrate that the spin of optically addressable point defects can be coherently driven with AC electric fields. Based on magnetic-dipole forbidden spin transitions, this scheme enables spatially confined spin control, the imaging of high-frequency electric fields, and the characterization of defect spin multiplicity. While we control defects in SiC, these methods apply to spin systems in many semiconductors, including the nitrogen-vacancy center in diamond. Electrically driven spin resonance offers a viable route towards scalable quantum control of electron spins in a dense array.
