ALBERT

Description: Author(s): C. C. Lo, V. Lang, R. E. George, J. J. L. Morton, A. M. Tyryshkin, S. A. Lyon, J. Bokor, and T. Schenkel We have measured the electrically detected magnetic resonance of donor-doped silicon field-effect transistors in resonant X - (9.7 GHz) and W -band (94 GHz) microwave cavities. The two-dimensional electron gas resonance signal increases by 2 orders of magnitude from X to W band, while the donor resona... [Phys. Rev. Lett. 106, 207601] Published Fri May 20, 2011

Description: Author(s): C. C. Lo, C. D. Weis, J. van Tol, J. Bokor, and T. Schenkel We demonstrate an all-electrical donor nuclear spin polarization method in silicon by exploiting the tunable interaction of donor bound electrons with a two-dimensional electron gas, and achieve over two orders of magnitude nuclear hyperpolarization at T =5  K and B =12  T with an in-plane magnetic fi... [Phys. Rev. Lett. 110, 057601] Published Thu Jan 31, 2013

Description: Author(s): G. Pica, B. W. Lovett, R. N. Bhatt, T. Schenkel, and S. A. Lyon A scaled quantum computer with donor spins in silicon would benefit from a viable semiconductor framework and a strong inherent decoupling of the qubits from the noisy environment. Coupling neighboring spins via the natural exchange interaction according to current designs requires gate control stru… [Phys. Rev. B 93, 035306] Published Thu Jan 14, 2016

Description: Controlling spin relaxation with a cavity Nature 531, 7592 (2016). doi:10.1038/nature16944 Authors: A. Bienfait, J. J. Pla, Y. Kubo, X. Zhou, M. Stern, C. C. Lo, C. D. Weis, T. Schenkel, D. Vion, D. Esteve, J. J. L. Morton & P. Bertet Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.

Description: We exposed nitrogen-implanted diamonds to beams of swift heavy ions (∼1 GeV, ∼4 MeV/u) and find that these irradiations lead directly to the formation of nitrogen vacancy (NV) centers, without thermal annealing. We compare the photoluminescence intensities of swift heavy ion activated NV − centers to those formed by irradiation with low-energy electrons and by thermal annealing. NV − yields from irradiations with swift heavy ions are 0.1 of yields from low energy electrons and 0.02 of yields from thermal annealing. We discuss possible mechanisms of NV center formation by swift heavy ions such as electronic excitations and thermal spikes. While forming NV centers with low efficiency, swift heavy ions could enable the formation of three dimensional NV − assemblies over relatively large distances of tens of micrometers. Further, our results show that NV center formation is a local probe of (partial) lattice damage relaxation induced by electronic excitations from swift heavy ions in diamond.

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weis, Christoph D -- Schenkel, Thomas -- England -- Nature. 2013 May 2;497(7447):46-7. doi: 10.1038/497046a.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23636392" target="_blank"〉PubMed〈/a〉

Description: Author(s): A. Bienfait, P. Campagne-Ibarcq, A. H. Kiilerich, X. Zhou, S. Probst, J. J. Pla, T. Schenkel, D. Vion, D. Esteve, J. J. L. Morton, K. Moelmer, and P. Bertet Electron-spin-resonance measurements can achieve greater sensitivity using squeezed light as an input. [Phys. Rev. X 7, 041011] Published Tue Oct 17, 2017

Description: Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bienfait, A -- Pla, J J -- Kubo, Y -- Zhou, X -- Stern, M -- Lo, C C -- Weis, C D -- Schenkel, T -- Vion, D -- Esteve, D -- Morton, J J L -- Bertet, P -- England -- Nature. 2016 Mar 3;531(7592):74-7. doi: 10.1038/nature16944. Epub 2016 Feb 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Quantronics Group, SPEC, CEA, CNRS, Universite Paris-Saclay, CEA-Saclay, 91191 Gif-sur-Yvette, France. ; London Centre for Nanotechnology, University College London, London WC1H 0AH, UK. ; Institute of Electronics Microelectronics and Nanotechnology, CNRS UMR 8520, ISEN Department, Avenue Poincare, CS 60069, 59652 Villeneuve d'Ascq Cedex, France. ; Quantum Nanoelectronics Laboratory, BINA, Bar Ilan University, Ramat Gan, Israel. ; Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26878235" target="_blank"〉PubMed〈/a〉

Description: Author(s): J. J. Pla, A. Bienfait, G. Pica, J. Mansir, F. A. Mohiyaddin, Z. Zeng, Y. M. Niquet, A. Morello, T. Schenkel, J. J. L. Morton, and P. Bertet Strain is known to impact the properties of spin-based quantum devices, altering spin-resonance frequencies and potentially affecting device reproducibility. Few studies have been performed to understand the effect of device strains on spins located near the micro- and nanostructures of a practical quantum device. This work uses high-sensitivity superconducting microresonators to measure the spin-resonance spectra of a small ensemble of bismuth donors in silicon. The observed spectrum is unlike that of the bulk, and is reproduced by finite-element strain modeling of the resonator, illustrating the importance of considering strain in device design. [Phys. Rev. Applied 9, 044014] Published Tue Apr 10, 2018

Description: We present a unique design and fabrication process for a lateral, gate-confined double quantum dot in an accumulation mode metal-oxide-semiconductor (MOS) structure coupled to an integrated microwave resonator. All electrostatic gates for the double quantum dot are contained in a single metal layer, and use of the MOS structure allows for control of the location of the two-dimensional electron gas via the location of the accumulation gates. Numerical simulations of the electrostatic confinement potential are performed along with an estimate of the coupling of the double quantum dot to the microwave resonator. Prototype devices are fabricated and characterized by transport measurements of electron confinement and reflectometry measurements of the microwave resonator.