The silicon metal-oxide-semiconductor (MOS) material system is a technologically important implementation of spin-based quantum information processing. However, the MOS interface is imperfect leading to concerns about 1/f trap noise and variability in the electron g-factor due to spin–orbit (SO) effects. Here we advantageously use interface–SO coupling for a critical control axis in a double-quantum-dot singlet–triplet qubit. The magnetic field-orientation dependence of the g-factors is consistent with Rashba and Dresselhaus interface–SO contributions. The resulting all-electrical, two-axis control is also used to probe the MOS interface noise. The measured inhomogeneous dephasing time, , of 1.6 μs is consistent with 99.95% 28Si enrichment. Furthermore, when tuned to be sensitive to exchange fluctuations, a quasi-static charge noise detuning variance of 2 μeV is observed, competitive with low-noise reports in other semiconductor qubits. This work, therefore, demonstrates that the MOS interface inherently provides properties for two-axis qubit control, while not increasing noise relative to other material choices.

A miniature, integrated chemical Iabaratory ().lChcmLab) is being developed that utilizes microfabrication to provide faster response, smaller size, lower power Operation, and an ability to utilize multiple analysis channels for enhanced versatility and chemical discrimination. Improved sensitivity and selectivity are achieved with three cascaded components: ( l) a sample collector/concentrator, (2) a gas chromatographic (GC) Separator, and (3) a chemically selective surface acoustic wave (SA W) array detector. Prototypes of all three components have been developed and demonstrated both individually and when integrated on a novel electrical and fluidic printed circuit board. A hand-held autonomaus system containing two analysis channels and all supporting electronics and user interfaces is currently being assembled and tested.

Abstract: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.Deterministic placement of single atoms is a key capability for fabrication of nanometer scale and single atom solid-state devices in a range of material systems including Si, diamond, and III-V compounds. Examples of Si-based devices include: donors coupled to quantum dots [1] for charge [2], electron [3,4], and nuclear spin [5,6] qubits (quantum bits) and acceptors coupled to silicon cavities to create phononic qubits [7]. Single color (defect) centers in diamond have a range of applications including metrology [8], quantum computing using nitrogen-vacancy (NV) centers [9] and coupling silicon-vacancy (SiV) centers to photonic cavities for cavity QED experiments [9,10]. In III-V materials, deterministic seeding of nucleation sites for controlling the quantum dot growth locations [11] has many potential applications including the development of single photon sources [12]. In many applications, placement of single ions within small volumes is critical. Ion implantation has been widely applied in the semiconductor industry for introducing dopants with a nominal depth and dose by varying the implant energy and the exposure time, respectively. The key challenges to extending this technique down to single atom control are the precise control over the atom's position and the implantation of one and only one atom. Techniques include in-situ ion detection using PIN diode detectors [13][14][15] and FinFETs [16,17] and detection of secondary electrons [18].We present a "top down" ion implantation approach to deterministic single atom device fabrication in Si and in other material systems suitable for ion detection including diamond [19] and GaAs [20]. This requires the ability to place the implanted ions with high positioning precision and deterministic control over the number of ions implanted. We use the nanoImplanter (nI) at Sandia National Labs (SNL), which is a direct-write focused ion beam platform to control the positioning of the implanted ion and in-situ solid-state detectors for single ion detection. We demonstrate single ion targeting to less than 35 nm allowing for deterministic single ion implantation. The combination of focused ion beams, direct write lithography, fast beam blanking and chopping, ion mass selectivity, in-situ detection and electrical probing are key features that enable rapid prototyping, customized implantation and high throughput fabrication of deterministic single atom devices. As a test of our "top-down" ion implantation and detection capability we...

Real‐time monitoring of an individual’s physiologic state without constant observation by a healthcare professional necessitates the construction of an autonomous remote diagnostic device that is capable of performing a wide range of diagnostic functions. For many applications, assessing the immediate physiologic state of an individual as he or she is continuously exposed to diverse environments would require complex dynamic chemical processing scenarios that are capable of real time readouts. We seek to answer these problems by combining in vivo microneedle platforms with multifunctional lab‐on‐chip electrode arrays that are capable of detecting a wide variety of relevant biomarkers. The results presented here provide an important proof‐of‐concept demonstration of integration of microneedles with a microchip platform containing fluidic channels and electrode transducers. As shown by immunoassay detection of myoglobin and troponin, such a device may be used to extract interstitial fluid and monitor biologically important molecules.

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.The spins of donor electrons in Si are promising candidates for quantum computing 1 because of long coherence times 2-4 and compatibility with existing fabrication technology. Single spin readout for donors in Si has been successfully demonstrated for P and Sb donors. 5,6 Entangled two-qubit operations, in addition to such single qubit operations, are required to form a universal developed using a focused ion beam and counting single ion implants can control both the number and the location. This control is necessary for future donor based spin qubit devices. AUTHOR INFORMATIONCorresponding Author *msingh@sandia.gov