arXiv subjects

D. R. Luhman

Publications and source records attributed to D. R. Luhman.

3 recordsLinked to original sources

arXiv2017

Ion Implantation for Deterministic Single Atom Devices

We demonstrate a capability of deterministic doping at the single atom level using a combination of direct write focused ion beam and solid-state ion detectors. The focused ion beam system can position a single ion to within 35 nm of a targeted location and the detection system is sensitive to single low energy heavy ions. This platform can be used to deterministically fabricate single atom devices in materials where the nanostructure and ion detectors can be integrated, including donor-based qubits in Si and color centers in diamond.

cond-mat.mes-hall↗

arXiv2015

Silicon Quantum Dots with Counted Antimony Donor Implants

Deterministic control over the location and number of donors is crucial to donor spin quantum bits (qubits) in semiconductor based quantum computing. In this work, a focused ion beam is used to implant antimony donors close to quantum dots. Ion detectors are integrated next to the quantum dots to sense the implants. The numbers of donors implanted can be counted to a precision of a single ion. In low-temperature transport measurements, regular coulomb blockade is observed from the quantum dots. Charge offsets indicative of donor ionization are also observed in devices with counted donor implants.

cond-mat.mes-hall↗

arXiv2008

Observation of a Fractional Quantum Hall State at $ν=1/4$ in a Wide GaAs Quantum Well

We report the observation of an even-denominator fractional quantum Hall (FQH) state at $ν=1/4$ in a high quality, wide GaAs quantum well. The sample has a quantum well width of 50 nm and an electron density of $n_e=2.55\times10^{11}$ cm$^{-2}$. We have performed transport measurements at $T\sim35$ mK in magnetic fields up to 45 T. When the sample is perpendicular to the applied magnetic field, the diagonal resistance displays a kink at $ν=1/4$. Upon tilting the sample to an angle of $θ=20.3^o$ a clear FQH state at emerges at $ν=1/4$ with a plateau in the Hall resistance and a strong minimum in the diagonal resistance.

cond-mat.mes-hall↗