Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session A40: Defects for Quantum ComputationsFocus
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Sponsoring Units: DMP Chair: Juan-Jose Lietor-Santos, American Physical Society Room: Room 232 |
Monday, March 6, 2023 8:00AM - 8:36AM |
A40.00001: Nasim Alem Invited Speaker: Nasim Alem
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Monday, March 6, 2023 8:36AM - 8:48AM |
A40.00002: Creating high-density NV- centers in CVD diamond using high-energy photons from Ar+ plasma Kapildeb Ambal, Prem Karki, Rupak Timalsina, Mohammadjavad Dowran, Abdelghani Laraoui High-density Nitrogen-Vacancy (NV) centers in diamond are among the most versatile quantum sensors used in many sensing applications, including magnetic field sensors [1]. The existing methods to create, such as high-density NV- centers, are expensive and cumbersome, often requiring a large dose of nitrogen implantation, degrading the quantum properties. The methods for the quick and efficient creation of NV- centers are still developing. In this talk, we present a novel and cost-effective approach to creating high-density NV- centers in a single crystal, CVD-grown diamond substrate with as-grown Nitrogen concentration < 1 ppm. We create a high-density NV- center by exposing the diamond substrate in Ar+ plasma for 30 s [2] followed by two hours of thermal annealing at 1100 oC. Based on optically detected magnetic resonance and fluorescence microscopy measurements, we estimate an NV- density of ~1015 cm-3 (~0.02 ppm), a four-fold higher than as-grown NV- concentration, distributed homogeneously over 200 um depth from the diamond surface. The created NVs have spin-lattice relaxation time (T1) of 5 ms and a spin-spin coherence time (T2) of 4 us. We measure a DC magnetic field sensetivity ~108 nT/ Hz1/2 using a sample volume of 0.2 um3. [1] V. M Acosta, et al., Phys. Rev. B 80 115202 (2009), [2] K. Ambal, et al., Phys. Rev. Applied 4, 024008 (2015). |
Monday, March 6, 2023 8:48AM - 9:00AM |
A40.00003: Numerical Modeling of Two-Defect Spin Dynamics in a Hyperfine Field Christopher J Ciccarino, Felipe H da Jornada, Prineha Narang Spins in solid state defects represent promising building blocks for quantum information applications. For these purposes, maintaining coherent spin states is crucial; however, long coherence is generally not straightforward to achieve, as spins can interact with various degrees-of-freedom of the solid state host. In many cases, hyperfine interactions between the electronic spin of the defect and the nuclear spins of the host lattice dominate decoherence. In these scenarios, the cluster-correlation expansion (CCE) method has proven to be a useful numerical tool in qualitatively and quantitatively capturing the effective spin coherence of the combined spin-bath system, and more recent generalizations have included population dynamics as well. In this work, we extend this generalized CCE method to capture the spin dynamics of two qubit spins coupled with a common bath of nuclear spins. Using this framework, we evaluate the spin dynamics in a variety of defect qubit candidate systems as a function of different defect pair separations, magnetic field strengths, and pulse sequence schemes. More broadly, our method can be used to systematically study the dynamical interactions of complex defect clusters and their coupling to the hyperfine spin bath. |
Monday, March 6, 2023 9:00AM - 9:12AM |
A40.00004: Brillouin – Mandelstam Spectroscopy of Acoustic Phonons in Boron-Doped Diamond – Implications for Thermal Management of Ultra-Wide-Band-Gap Electronics Erick A Guzman, Alexander A Balandin, Fariborz Kargar, Timothy A Grotjohn, Frank Angeles, Reza Vatan Meidanshahi, Dylan Wright, Richard Wilson, Stephen Goodnick We investigated bulk and surface acoustic phonons in the boron-doped single-crystal diamond films using the Brillouin-Mandelstam light scattering spectroscopy. It was found that the frequency and the group velocity of acoustic phonons decrease non-monotonically with the increasing boron doping concentration, revealing pronounced phonon softening. The change in the velocity of the shear horizontal acoustic phonons in the degenerately doped diamond was as large as ~15% as compared to the undoped diamond [1]. As a result of boron doping, the velocity of the bulk longitudinal and transverse acoustic phonons decreased correspondingly. The frequency of the optical phonons was unaffected at low boron concentrations but experienced a strong decrease at the high doping level. The obtained results have important implications for thermal transport in heavily doped diamond films used for ultra-wide-band-gap electronics. In evaluating the thermal conductivity of doped diamond films, one should take into consideration not only the concentration of dopants acting as scattering centers but also the changes in the acoustic phonon velocities. |
Monday, March 6, 2023 9:12AM - 9:24AM |
A40.00005: Integration of Nanoscale Materials for Quantum Sensing with Nitrogen-Vacancy Centers. Jacob D Henshaw, Pauli Kehayias, Luca Basso, Rong Cong, Tzu-Ming Lu, Michael P Lilly, Andrew M Mounce The nitrogen-vacancy (NV) color center in diamond is an established nanoscale quantum sensor able to detect the magnetic and electronic properties of low-dimensional materials, such as hBN, graphene, and thin metal films. However, integration of materials with the NV can have complex positive and negative consequences for sensing, due to the interaction between the target material and the sensor resulting in a reduction of NV spin lifetimes and photoluminescence rates. Further, metals and high work function materials can induce band bending and destabilize the charge environment resulting in the magnetically sensitive NV- converting to a magnetically insensitive charge state, NV0. On the other hand, some of these complications can be turned into advantages, for instance the band bending caused by metals can deplete magnetic noise sources of electrons, increasing spin lifetime. In this talk, I will present our work integrating NV-rich diamond with quantum materials while maintaining or even enhancing the quality of NV sensors. We characterize a series of NV ensembles at variable depth influenced by band-bending metals deposited on the diamond to understand the optimal tradeoff between charge conversion and sensitivity. |
Monday, March 6, 2023 9:24AM - 9:36AM |
A40.00006: Towards coherent charge transport between individual nitrogen vacancy centers in diamond as a platform for quantum information processing Artur Lozovoi, Yunheng Chen, Gyorgy Vizkelethy, Edward S Bielejec, Johannes Flick, Marcus William Doherty, Carlos A Meriles Color centers in wide bandgap semiconductors emerged as one of the major material platforms for quantum information science, quantum computing and sensing, with nitrogen vacancy center (NV) in diamond being one of the most promising qubit candidates. While the nanoscale quantum registers with 10 qubits and the long-distance entanglement between 3 NV nodes have been demonstrated, scaling to a larger number of qubits remains an outstanding challenge. Here, we discuss the possibility of using photoionized charge carriers for quantum information transfer between NV qubits. Following our recent observation of a giant hole capture cross section by an NV- center, we further explore the ways to increase the fidelity of the transport process in order to approach the regime of a single carrier capture detection with a possibility to then probe its spin. We experimentally demonstrate the effect of the externally applied electric fields on the hole capture probability by the NV- and its temperature dependence. We also develop a semiclassical Monte Carlo model that successfully describes the details of carrier propagation and capture by the trap under the conditions used in the experiment. A more detailed description of a hole capture through a series of weakly bound excitonic levels within the Coulombic potential at the site of NV- is developed through solving the effective mass equations with the input from the first-principles calculations. |
Monday, March 6, 2023 9:36AM - 9:48AM |
A40.00007: Quantifying NV-center Spectral Diffusion by Symmetry Brendan A McCullian, Harry Cheung, Huiyao Chen, Johnny C Crossman, Gregory D Fuchs Solid-state defects are a leading platform for quantum networking owing to their spectrally narrow, spin-dependent optical transitions. A central challenge for scalability of defect-based networking schemes is spectral diffusion of the optical transitions, which limits the entanglement generation rate. In this presentation I will discuss our recent study of several nitrogen-vacancy (NV) centers in bulk diamond. We quantify the photoinduced spectral diffusion caused by the interaction of a charge-state initialization laser with the local electromagnetic environment, as well as the static strain and depth of each defect. To learn more about the origin of the fluctuations, we decompose the spectral diffusion and static strain into components corresponding to Jahn-Teller symmetries of the NV center. We then compute correlations between the various components of spectral diffusion, strain, and depth and look for underlying physics. Our analysis uncovers three key results. First, both spectral diffusion and strain are dominated by perturbations along the NV center's symmetry axis. Second, off-axis strain can protect from some components of off-axis spectral diffusion. Third, optical aberrations with increasing depth can lead to increased spectral diffusion. Our symmetry-decomposed technique for quantifying spectral diffusion can be applied to other solid-state defects of interest and can aid in understanding, and ultimately mitigating, sources of spectral diffusion. |
Monday, March 6, 2023 9:48AM - 10:00AM |
A40.00008: Scalable quantum memory nodes using nuclear spins in Silicon Carbide Roland Nagy, Shravan Parthasarathy, Birgit Kallinger, Florian Kaiser, Patrick Berwian, Durga Dasari, Jochen Friedrich A distributed quantum network would require quantum nodes capable of performing arbitrary quantum information protocols with high fidelity. So far the challenge has been in realizing such quantum nodes with features for scalable quantum computing. We show here that using the solidstate spins in 4H-Silicon Carbide (4H-SiC) such a goal could be realized, wherein a controlled generation of highly coherent qubit registers using nuclear spins is possible. Using a controlled isotope concentration and coherent control we perform here atomistic modeling of the central spin system formed by the electron spin of a silicon vacancy color center (V −Si-center) and the noninteracting nuclear spins. From this we lay out conditions for realizing a scalable nuclear-spin (13C or 29Si) register, wherein independent control of the qubits alongside their mutual controlled operations using the central electron spin associated to the V − Si-center in 4H-SiC are achieved. Further, the decoherence and entanglement analysis provided here could be used to evaluate the |
Monday, March 6, 2023 10:00AM - 10:12AM |
A40.00009: Multiplexed Data Storage at Cryogenic Temperatures in Diamond Richard G Monge, Tom Delord, Carlos A Meriles Wide bandgap semiconductors host point defects whose absorption characteristics are known to give gems their signature color. These color centers feature metastable charge states that can be interconverted with the help of optical excitation at select wavelengths. The distinct fluorescence and spin properties in each of these states have already been exploited to show storage of classical information in three dimensions, but the memory capacity of color center platforms has been limited thus far by optical diffraction. Here, we leverage strain-induced heterogeneity in the optical transitions of the nitrogen-vacancy (NV) center in diamond to demonstrate sub-diffraction charge state control of individual point defects. We first focus on pairs of color centers within the same diffraction-limited volume and show selective charge state preparation of individual NVs. Further, we extend this approach to dense color center ensembles, and show rewritable, wavelength-multiplexed data storage with large areal densities. These results portend opportunities for alternative approaches to information processing in the form of devices with enhanced optical storage capacity. |
Monday, March 6, 2023 10:12AM - 10:24AM |
A40.00010: Demonstration of NV-detected NMR at 8.3 Tesla Yuhang Ren, Michael Coumans, Dylan Kawashiri, Cooper M Selco, Alejandro Reyes, Benjamin Fortman, Susumu Takahashi Nuclear magnetic resonance (NMR) is an invaluable spectroscopic technique for the characterization of molecular structures. NMR at high magnetic fields is highly advantageous because of its high resolution and improved sensitivity, enabling the resolution of small chemical shifts and offering new insights into the study of complex molecules. The nitrogen-vacancy (NV) center in diamond has enabled widespread study of nanoscale NMR and electron spin resonance (ESR) at low magnetic fields [1]. However, conventional NV-detected NMR based on AC magnetic field sensing is not applicable at high fields, therefore requires the development of alternate techniques. Furthermore, there have been few studies of NV-detected NMR at high fields due to technical challenges [2]. In this presentation, we explore an NV-detected NMR technique suitable for applications of high-field NMR [3]. We demonstrate optically detected magnetic resonance (ODMR) with the NV Larmor frequency of 230 GHz at 8.3 T, corresponding to a proton NMR frequency of 350 MHz. We demonstrate the first measurement of electron-electron double resonance detected NMR (EDNMR) using the NV center and successfully detect 13C nuclear bath spins. This work demonstrates a clear path to nanoscale NMR of external spins and NV-detected NMR at even higher magnetic fields. |
Monday, March 6, 2023 10:24AM - 10:36AM |
A40.00011: Non-Markovian Spin-Bath Dynamics of a Single Nitrogen-Vacancy Center in Diamond Cooper M Selco, Daniel A Lidar, Susumu Takahashi, Nicholas Musat, Michael Coumans, Kyle Shi For many experiments in quantum information science, it is essential to protect quantum coherence from environmental decoherence sources. While stochastic (Markovian) processes of the decoherence have been studied extensively, non-Markovian processes are often overlooked since they are not captured by simple models. In principle, non-Markovian environmental bath dynamics can present a perspective for understanding and combating quantum decoherence. |
Monday, March 6, 2023 10:36AM - 10:48AM |
A40.00012: Photonic Structures and Divacancy Defects in the 4H-SiC-on-Insulator Platform Brett Yurash, Biqin Huang, Samuel J Whiteley, Tsung L Yang, Shanying Cui, Thaddeus D Ladd Fully integrated, chip-scale devices are envisioned to serve as nodes in a quantum network. Fabrication of these devices would be greatly facilitated by a CMOS-foundry-compatible monolithic material platform capable of hosting key elements such as spin qubits, low-loss photonic waveguides, nonlinear optical elements (i.e. for frequency conversion and entangled photon pair generation), electro-optically tunable components (i.e. for switches and filters), and single-photon detectors. To this end, 4H silicon carbide (4H-SiCOI) is a promising monolithic platform for mass production of quantum integrated photonic circuits. However, a key remaining challenge is the integration of the above-mentioned components into a single device. In this talk we will discuss our work on producing 100 mm diameter wafers of thin film 4H-SiCOI and fabricating single mode photonic waveguide structures with low loss (< 10 dB/cm) across a large spectral region spanning the near infrared to telecom wavelengths. We will then highlight our work on integrating divacancy defect ensembles into these low loss waveguides. Finally, we will show our progress toward optically detected spin resonance of these near-infrared emitting divacancy defect ensembles using integrated superconducting nanowire single-photon detectors (SNSPDs). Our progress with these integrated devices shows that 4H-SiCOI is a promising material platform for quantum integrated photonics. |
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