113 research outputs found
Electrically detected magnetic resonance using radio-frequency reflectometry
The authors demonstrate readout of electrically detected magnetic resonance
at radio frequencies by means of an LCR tank circuit. Applied to a silicon
field-effect transistor at milli-kelvin temperatures, this method shows a
25-fold increased signal-to-noise ratio of the conduction band electron spin
resonance and a higher operational bandwidth of > 300 kHz compared to the kHz
bandwidth of conventional readout techniques. This increase in temporal
resolution provides a method for future direct observations of spin dynamics in
the electrical device characteristics.Comment: 9 pages, 3 figure
Acoustically driven ferromagnetic resonance
Surface acoustic waves (SAW) in the GHz frequency range are exploited for the
all-elastic excitation and detection of ferromagnetic resonance (FMR) in a
ferromagnetic/ferroelectric (nickel/lithium niobate) hybrid device. We measure
the SAW magneto-transmission at room temperature as a function of frequency,
external magnetic field magnitude, and orientation. Our data are well described
by a modified Landau-Lifshitz-Gilbert approach, in which a virtual,
strain-induced tickle field drives the magnetization precession. This causes a
distinct magnetic field orientation dependence of elastically driven FMR that
we observe in both model and experiment.Comment: 4 page
Lock-in detection for pulsed electrically detected magnetic resonance
We show that in pulsed electrically detected magnetic resonance (pEDMR)
signal modulation in combination with a lock-in detection scheme can reduce the
low-frequency noise level by one order of magnitude and in addition removes the
microwave-induced non-resonant background. This is exemplarily demonstrated for
spin-echo measurements in phosphorus-doped Silicon. The modulation of the
signal is achieved by cycling the phase of the projection pulse used in pEDMR
for the read-out of the spin state.Comment: 4 pages, 2 figure
Architecture for high-sensitivity single-shot readout and control of the electron spin of individual donors in silicon
We describe a method to control and detect in single-shot the electron spin
state of an individual donor in silicon with greatly enhanced sensitivity. A
silicon-based Single-Electron Transistor (SET) allows for spin-dependent
tunneling of the donor electron directly into the SET island during the
read-out phase. Simulations show that the charge transfer signals are typically
\Delta q > 0.2 e - over an order of magnitude larger than achievable with
metallic SETs on the SiO2 surface. A complete spin-based qubit structure is
obtained by adding a local Electron Spin Resonance line for coherent spin
control. This architecture is ideally suited to demonstrate and study the
coherent properties of donor electron spins, but can be expanded and integrated
with classical control electronics in the context of scale-up.Comment: 5 pages, 4 figure
Broadband electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor
We report electrically detected magnetic resonance of phosphorus donors in a
silicon field-effect transistor. An on-chip transmission line is used to
generate the oscillating magnetic field allowing broadband operation. At
milli-kelvin temperatures, continuous wave spectra were obtained up to 40 GHz,
using both magnetic field and microwave frequency modulation. The spectra
reveal the hyperfine-split electron spin resonances characteristic for Si:P and
a central feature which displays the fingerprint of spin-spin scattering in the
two-dimensional electron gas.Comment: 4 pages, 4 figures, submitted to AP
Laser-heated capillary discharge plasma waveguides for electron acceleration to 8 GeV
A plasma channel created by the combination of a capillary discharge and inverse Bremsstrahlung laser heating enabled the generation of electron bunches with energy up to 7.8 GeV in a laser-driven plasma accelerator. The capillary discharge created an initial plasma channel and was used to tune the plasma temperature, which optimized laser heating. Although optimized colder initial plasma temperatures reduced the ionization degree, subsequent ionization from the heater pulse created a fully ionized plasma on-axis. The heater pulse duration was chosen to be longer than the hydrodynamic timescale of ≈ 1 ns, such that later temporal slices were more efficiently guided by the channel created by the front of the pulse. Simulations are presented which show that this thermal self-guiding of the heater pulse enabled channel formation over 20 cm. The post-heated channel had lower on-axis density and increased focusing strength compared to relying on the discharge alone, which allowed for guiding of relativistically intense laser pulses with a peak power of 0.85 PW and wakefield acceleration over 15 diffraction lengths. Electrons were injected into the wake in multiple buckets and times, leading to several electron bunches with different peak energies. To create single electron bunches with low energy spread, experiments using localized ionization injection inside a capillary discharge waveguide were performed. A single injected bunch with energy 1.6 GeV, charge 38 pC, divergence 1 mrad, and relative energy spread below 2% full-width half-maximum was produced in a 3.3 cm-long capillary discharge waveguide. This development shows promise for mitigation of energy spread and future high efficiency staged acceleration experiments
Electrostically defined few-electron double quantum dot in silicon
A few-electron double quantum dot was fabricated using
metal-oxide-semiconductor(MOS)-compatible technology and low-temperature
transport measurements were performed to study the energy spectrum of the
device. The double dot structure is electrically tunable, enabling the
inter-dot coupling to be adjusted over a wide range, as observed in the charge
stability diagram. Resonant single-electron tunneling through ground and
excited states of the double dot was clearly observed in bias spectroscopy
measurements.Comment: 4 pages, 3 figures, accepted for Applied Physics Letter
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