A silicon carbide room temperature single-photon source

Over the past few years, single-photon generation has been realized in numerous systems: single molecules 1 , quantum dots 2-4 , diamond colour centres 5 and others 6 . The generation and detection of single photons play a central role in the experimental foundation of quantum mechanics 7 and measurement theory 8 . An efficient and high-quality single-photon source is needed to implement quantum key distribution, quantum repeaters and photonic quantum information processing 9 . Here we report the identification and formation of ultrabright, room-temperature, photostable single-photon sources in a device-friendly material, silicon carbide (SiC). The source is composed of an intrinsic defect, known as the carbon antisite- vacancy pair, created by carefully optimized electron irradiation and annealing of ultrapure SiC. An extreme brightness (210 6 counts s 1 ) resulting from polarization rules and a high quantum efficiency is obtained in the bulk without resorting to the use of a cavity or plasmonic structure. This may benefit future integrated quantum photonic devices 9

Dopant effects on the photoluminescence of interstitial-related centers in ion implanted silicon

The dopant dependence of photoluminescence(PL) from interstitial-related centers formed by ion implantation and a subsequent anneal in the range 175–525 °C is presented. The evolution of these centers is strongly effected by interstitial-dopant clustering even in the low temperature regime. There is a significant decrease in the W line (1018.2 meV) PL intensity with increasing B concentration. However, an enhancement is also observed in a narrow fabrication window in samples implanted with either P or Ga. The annealtemperature at which the W line intensity is optimized is sensitive to the dopant concentration and type. Furthermore, dopants which are implanted but not activated prior to low temperature thermal processing are found to have a more detrimental effect on the resulting PL. Splitting of the X line (1039.8 meV) arising from implantation damage induced strain is also observed.This work is supported by a grant from the Australian Research Council. B.C.J. is partially supported by the Japan Society for the Promotion of Science (JSPS) (Grant-in-aid for Scientific Research, 22.00802)

Hydrogen resist lithography and electron beam lithography for fabricating silicon targets for studying donor orbital states

Recently, phosphorous structures in silicon have been of interest theoretically and experimentally due to their relevance in the field of quantum computing. Coherent control of the orbital states of shallow donors in silicon has been demonstrated in bulk doped samples. Here we discuss the fabrication techniques required to 1) obtain patterned two dimensional dilute sheets of impurities in silicon of controlled doping densities 2) get them to act as targets for a terahertz laser. Scanning tunnelling microscope hydrogen lithography enables patterning of impurity features in silicon with a resolution from 1nm to tens of nm. Molecular beam epitaxy is used for a protective thin-film crystalline silicon growth over the impurity sheet. Electron beam lithography coupled with reactive ion etching allows features from tens to hundreds of microns to be etched into the silicon with 10 to 20nm resolution. The experimental readout is achieved via illumination of the silicon target by terahertz light and subsequent electrical detection. The electrical signal comes from coherent and non-linear excitations of the impurity electrons. This detection technique enables the precision condensed matter samples to remain intact after exposure to the free electron laser pulse

以書付奉伺候（十五軒程当時相休居候、旅籠取立云々）

Superposition of orbital eigenstates is crucial to quantum technology utilizing atoms, such as atomic clocks and quantum computers, and control over the interaction between atoms and their neighbours is an essential ingredient for both gating and readout. The simplest coherent wavefunction control uses a two-eigenstate admixture, but more control over the spatial distribution of the wavefunction can be obtained by increasing the number of states in the wavepacket. Here we demonstrate THz laser pulse control of Si:P orbitals using multiple orbital state admixtures, observing beat patterns produced by Zeeman splitting. The beats are an observable signature of the ability to control the path of the electron, which implies we can now control the strength and duration of the interaction of the atom with different neighbours. This could simplify surface code networks which require spatially controlled interaction between atoms, and we propose an architecture that might take advantage of this

Corrigendum: Coherent creation and destruction of orbital wavepackets in Si:P with electrical and optical read-out

The ability to control dynamics of quantum states by optical interference, and subsequent electrical read-out, is crucial for solid state quantum technologies. Ramsey interference has been successfully observed for spins in silicon and nitrogen vacancy centres in diamond, and for orbital motion in InAs quantum dots. Here we demonstrate terahertz optical excitation, manipulation and destruction via Ramsey interference of orbital wavepackets in Si:P with electrical read-out. We show milliradian control over the wavefunction phase for the two-level system formed by the 1s and 2p states. The results have been verified by all-optical echo detection methods, sensitive only to coherent excitations in the sample. The experiments open a route to exploitation of donors in silicon for atom trap physics, with concomitant potential for quantum computing schemes, which rely on orbital superpositions to, for example, gate the magnetic exchange interactions between impurities

Static and time-resolved mid-infrared spectroscopy of Hg0.95Cd0.05Cr2Se4 spinel

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P-2 dimer implantation in silicon: A molecular dynamics study

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A Room temperature single photon source in silicon carbide

We report the first observation of stable single photon sources in an electronic and photonic device-friendly material, silicon carbide (SiC). SiC is a viable material for implementing quantum communication, computation and photonic technologies.2 page(s

The Quadratic Zeeman effect used for state-radius determination in neutral donors and donor bound excitons in Si:P

We have measured the near-infrared photoluminescence spectrum of phosphorus doped silicon (Si: P) and extracted the donor-bound exciton (D0X) energy at magnetic fields up to 28 T. At high field the Zeeman effect is strongly nonlinear because of the diamagnetic shift, also known as the quadratic Zeeman effect (QZE). The magnitude of the QZE is determined by the spatial extent of the wave-function. High field data allows us to extract values for the radius of the neutral donor (D0) ground state, and the light and heavy hole D0X states, all with more than an order of magnitude better precision than previous work. Good agreement was found between the experimental state radius and an effective mass model for D0. The D0X results are much more surprising, and the radius of the mJ=±3/2 heavy hole is found to be larger than that of the mJ=±1/2 light hole