Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session D65: Defects and Dopants in Bulk Materials IFocus
|
Hide Abstracts |
Sponsoring Units: DMP Chair: Xuedan Ma, Argonne Natl Lab Room: Mile High Ballroom 4F |
Monday, March 2, 2020 2:30PM - 3:06PM |
D65.00001: Electrical and optical control of single spins in a silicon carbide semiconductor device Christopher Anderson, Alexandre Bourassa, Kevin Miao, Gary Wolfowicz, Peter J Mintun, Alexander Crook, Hiroshi Abe, Jawad Ul-Hassan, Nguyen T Son, Takeshi Ohshima, David Awschalom Defect spin qubits in silicon carbide (SiC) combine near-telecom operation and long coherence with a host crystal amenable to wafer scale semiconductor device engineering[1]. In particular, the neutral divacancy (VV0) in SiC has a spin-photon interface ideal for long distance quantum communications and repeater schemes[2]. Here, we isolate for the first time single VV0 defects in functioning, doped semiconductor p-i-n diodes and use the device to control the charge states of these defects[3]. This integration of the single spin into the semiconductor junction not only allows for a drastic reduction in spectral diffusion of the emitter, but also a careful study of the defect’s charge state under illumination. We focus on these photodynamics and demonstrate deterministic and optimized charge control of the defect, allowing for charge state stabilization and electrical gating of single photon emission. We discuss the outlook for electrical control, manipulation and readout of both the spin and charge degrees of freedom in these quantum emitters. |
Monday, March 2, 2020 3:06PM - 3:18PM |
D65.00002: Jahn-Teller Effects in Group IV Quantum Defects in Diamond Christopher Ciccarino, Johannes Flick, Matthew Trusheim, Prineha Narang
|
Monday, March 2, 2020 3:18PM - 3:30PM |
D65.00003: Group III Defects in Diamond for Quantum Information Applications Isaac Harris, Christopher Ciccarino, Matthew Trusheim, Johannes Flick, Dirk R. Englund, Prineha Narang Point defects in wide bandgap semiconductors have emerged as leading spin-photon interfaces for applications in quantum information science. In particular, several types of color centers in diamond have been characterised as promising candidates for spin-photon interfaces. However, no color center has yet demonstrated the required spin initialisation, spin coherence and optical stability required for easy integration into quantum devices. Here, we discuss theoretical and experimental results for a new class of color centers, the group III vacancy complexes in diamond, and in particular the negatively-charged gallium vacancy center. These group III color centers are predicted to be stable in an inversion-symmetric configuration, which makes their optical transition resilient to charge noise, and therefore well-suited to integration in nanostructures. Furthermore, they are thermodynamically stable in a spin-1 charge state, which gives them desirable level structures and spin coherence properties for quantum information applications. Based on these results, we comment on the suitability of these new color centers as spin-photon interfaces. |
Monday, March 2, 2020 3:30PM - 3:42PM |
D65.00004: First-principles characterization of nitrogen-related spin-defects in 4H- and 6H-SiC Yizhi Zhu, Giulia Galli Optically active spin defects in wide-gap semiconductors are promising platforms for solid-state quantum technologies. For example, in the last few years several defect qubits with long coherence times have been realized in SiC, an attractive material due to its ease of growth and microfabrication, compared to diamond. Recent studies [1-3] have explored the possibility of realizing a nitrogen vacancy (NV) in SiC, in analogy with diamond. We used first-principles calculations based on density functional theory to identify fingerprints of nitrogen related spin-defects in SiC. We computed several properties of point-defects containing nitrogen impurities, including zero-fielding splitting, hyperfine tensors, and zero-phonon lines. In order to analyze the robustness of our results, we conducted sensitivity analysis to establish the effect of pseudopotentials, density functionals and optimized atomistic structures on the computed electronic and spectroscopic properties of the defects. |
Monday, March 2, 2020 3:42PM - 3:54PM |
D65.00005: Vanadium spin qubits as telecom quantum emitters in silicon carbide Gary Wolfowicz, Christopher Anderson, Berk Diler, Oleg G. Poluektov, Joseph P Heremans, David Awschalom Solid state quantum emitters with addressable spin registers are promising platforms for quantum communication, yet few emit in the telecom band necessary for low-loss fiber networks. Here we create and isolate single vanadium dopants in silicon carbide (SiC) with emission in the O-band (~1300 nm) and with brightness allowing cavity-free detection, in a wafer scale CMOS-compatible material [1]. We demonstrate that their emission is stable and narrow near surfaces, enabling integration with nanoscale devices. |
Monday, March 2, 2020 3:54PM - 4:06PM |
D65.00006: Finite-size and Surface effects: Deep Defects in Nanostructured SiC Tamanna Joshi, Pratibha Dev Spin-active deep defects in wide-bandgap semiconductors like silicon carbide (SiC) are being studied for application in quantum technologies, such as quantum computing, and nanoscale field sensing. Often these applications involve nanostructuring of the host semiconductor. In a nanostructure, the electronical and optical properties are expected to be affected by surface and quantum confinement effects. In our work, we investigate these finite size effects by studying the properties of silicon vacancies with different charge states in 2H-SiC (wurtzite) nanowires. Defect properties like formation energy, spin, and spin polarization energies are shown to be site-dependent in the nanostructured host. Our results indicate that a surface acts as a sink for the defects, and the migration of defects towards the surface may lead to the loss of the signal from a defect placed in a nanostructured host. |
Monday, March 2, 2020 4:06PM - 4:18PM |
D65.00007: Formation and migration of vacancies in SiC Elizabeth Lee, Juan De Pablo, Giulia Galli Divacancy spin defects in silicon carbide (SiC) are promising platforms for quantum information science applications. However, the formation mechanism and migration properties of point defects in SiC are poorly understood and hence difficult to control. Using advanced simulation techniques, we gain insight into the creation, interaction and migration of vacancies in SiC, aimed at deriving rules for the design of robust defects in scalable quantum materials. In particular, we used a combination of enhanced sampling methods (https://github.com/MICCoM/SSAGES-public) coupled with classical Molecular Dynamics, and Density Functional Theory to investigate the defect electronic properties. We compare our results with thermal annealing and photoluminescence experiments [1], and we discuss possible processing conditions for the formation of divacancy defects with favorable spin states. |
Monday, March 2, 2020 4:18PM - 4:30PM |
D65.00008: Coherent control and high-fidelity readout of chromium ions in commercial silicon carbide Berk Diler, Samuel J Whiteley, Christopher Anderson, Gary Wolfowicz, Marie Wesson, Edward S Bielejec, Joseph P Heremans, David Awschalom Transition metal ions provide a rich set of optically active defect spins in wide bandgap semiconductors. Their extrinsic nature promises easy device integration through nano implantation. Specifically, chromium in the 4+ charge state (Cr4+) in silicon carbide (SiC) produces an S = 1 ground state and an S = 0 excited state with a strain insensitive near-telecom Λ-like optical-spin interface. In previous demonstrations the ground state spin control was limited by material quality. In this work [1], we study the formation Cr4+ in a commercial SiC substrate through implantation and annealing, enabling optical and coherent spin characterization. We measure an ensemble optical hole linewidth of 31 MHz, an order of magnitude narrower compared to as-grown samples. Through a detailed investigation of the Cr4+ governing transition dynamics, we optimize for high readout fidelities (79%). We report T1 times greater than 1 s at T = 15 K with a T2* = 317 ns and a T2 = 81 μs limited by the ensemble density. These results demonstrate Cr4+ in SiC to be an optically active spin-qubit for integration within hybrid quantum devices. |
Monday, March 2, 2020 4:30PM - 4:42PM |
D65.00009: Decoherence of diamond NV ensembles with varying nitrogen spin concentration: a cluster expansion study Huijin Park, Junghyun Lee, Sang-Yun Lee, Hosung Seo Nitrogen-vacancy (NV) centers in diamond have been developed into essential hardware units to develop a wide range of solid-state quantum technologies. For such applications, the long coherence time of NV centers is crucial. Numerous previous studies identified that the NV’s decoherence is often governed by the magnetic noise produced by the 13C nuclear spin bath and the nitrogen (P1) electron spin bath in a diamond. While the 13C-induced decoherence has been well understood, understanding of the P1-driven decoherence is still incomplete. In this study, we aim at the systematic theoretical investigation on the P1-driven decoherence of NV ensembles with varying P1 concentrations from 1ppm to 100ppm. We employ a cluster correlation expansion method. We discuss our results in comparison with recently published experimental data [1,2] and previous theoretical results [3,4]. Our results provide not only a microscopic understanding of the NV decoherence but also useful information to optimize the NV’s performance in various quantum applications such as NV-based magnetometry and NV-based quantum registers. |
Monday, March 2, 2020 4:42PM - 4:54PM |
D65.00010: Dynamics of Silicon-Vacancy Color Center in Nanodiamonds Chunjing Jia, Yan-Kai Tzeng, Yu Lin, Thomas Devereaux, Steven Chu Diamond-based color centers have emerged for a variety of applications in quantum communication, quantum photonics, and biological sciences, etc. Optical color center of SiV formed by one silicon atom sited in the middle of two vacancies shows great promise as a single-photon source. Unlike the NV center, which can be improved sufficiently for quantum applications by high-temperature annealing to mobilize only vacancies, SiV center may become unstable in diamond lattice under annealing. Upon annealing to temperatures up to 800 °C, both SiVs and vacancies would become mobile to the surface of diamond. It is unclear during the annealing process whether SiV or vacancy impurity migration dominates and the relative time-scale of the two processes. In this talk, we are going to present our studies to unravel this problem. An AOM-modulated laser heating and annealing in a diamond anvil cell has been used. The fluorescent intensities of SiV center before and after the annealing were measured using fluorescent spectroscopy. ab initio DFT calculations were used to quantify the dynamics of two impurities. Both experimental and theoretical results suggest that SiV centers can be stabilized associated with the crystalline quality during the production of artificial SiV photonic centers. |
Monday, March 2, 2020 4:54PM - 5:06PM |
D65.00011: Study of the Structure-property Relationship in Diamond (100), (110) and (111) Surfaces Hector Gomez, Michael Groves, Mahesh R Neupane Understanding the electronic and physical properties of reconstructed diamond (100), (110), and (111) is important for meeting the increasing demand for high-powered control electronics in harsh environments. By determining the electronic and structural properties of reconstructed diamond (100), (110), and (111) surfaces, the effect reconstruction has on its electronic properties versus an ideal surface is revealed. Using GPAW, a density-functional theory (DFT) and the AutoNEB package, a stepwise surface reconstruction for diamond (111) and (100) was modeled. Diamond (100) reconstruction demonstrated an exothermic reaction with no observable intermediates or transition states. Following reconstruction in the (100) phase, -0.254 eV/atom energetic variance was observed from the bulk-like surface. In the (111) phase, a never before predicted intermediate state, with per atom energy difference of -0.011 eV from the bulk-like 2X1 surface, was observed between the bulk-like and Pandey-chain surfaces. Observed stable Pandey-chain reconstructed state resulted in an energy difference of -0.109 eV/atom from its bulk-like counterpart. Lastly, the favorability of the reconstruction suggests that 2x1 diamond (100) and (111) will follow this configuration instead of the bulk-like surface. |
Monday, March 2, 2020 5:06PM - 5:18PM |
D65.00012: The Spin-Flip Bethe-Salpeter Equation approach, and applications to molecular magnets and defects in solids for quantum information Bradford Barker, David Strubbe Molecular magnets containing transition metals (e.g. Cr, Mn, Fe) are promising candidates for qubits due to their unpaired spins. Description of their ground- and excited-state energies is quite challenging for electronic structure methods, as these systems are poorly described by single-reference electronic-structure methods. The “spin flip” approach allows such methods to describe open-shell states as an excitation -- up or down in energy -- from a related single-reference high-spin state. Spin-flip time-dependent density-functional theory (TDDFT) has shown moderate successes in describing their energies, as well as their Heisenberg exchange coupling constants. The GW/Bethe-Salpeter equations have a similar form to TDDFT, but provide an ab initio kernel that overcomes many problems of standard TDDFT approximations. We have implemented spin-flip Bethe-Salpeter, allowing more accurate calculations on molecules, and enabling spin-flip for extended systems such as defects in solids for quantum information. We consider transition-metal dimers Mn2 and Cr2, and other molecular magnets, as well as the well-known diamond NV- center. |
Monday, March 2, 2020 5:18PM - 5:30PM |
D65.00013: NV-color centers in nanodiamond as a photon emitter embedded in whispering-gallery-mode optical resonator Sungwan Cho, Muhammed Kaan Yildiz, In Hwan Do, Dong-In Jung, Jung Hyun Shim, Ki Seok Hong, Hee Jin Lim, Jae Hoon Lee, Hyun Gyu Hong, Jung Bae Yoon, Dong Hun Lee, Hansuek Lee Development of reliable and stable photon source is crucial for applications in quantum technology, as well as fundamental experiment and metrology. NV(Nitrogen-vacancy) color center in diamond, are among the promising candidate for photon source. Although coupling of color centers with an high-Q optical cavity has high potential, fabricating optical cavities embedding defect centers have been challenging tasks with recent initial demonstrations. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700