Atomically thin circuits have recently been explored for applications in next-generation electronics and optoelectronics and have been demonstrated with two-dimensional lateral heterojunctions. In order to form true 2D circuitry from a single material, electronic properties must be spatially tunable. Here, we report tunable transport behavior which was introduced into single layer tungsten diselenide and tungsten disulfide by focused He + irradiation. Pseudometallic behavior was induced by irradiating the materials with a dose of ~1x10 16 He + /cm 2 to introduce defect states, and subsequent temperature-dependent transport measurements suggest a nearest neighbor hopping mechanism is operative. Scanning transmission electron microscopy and electron energy loss spectroscopy reveal that Se is sputtered preferentially, and extended percolating networks of edge states form within WSe2 at a critical dose of 1x10 16 He + /cm 2 . First-principles calculations confirm the semiconductor-to-metallic transition of WSe2 after pore and edge defects were introduced by He + irradiation. The hopping conduction was utilized to direct-write resistor loaded logic circuits in WSe2 and WS2 with a voltage gain of greater than 5. Edge contacted thin film transistors were also fabricated with a high on/off ratio (> 10 6 ), demonstrating potential for the formation of atomically thin circuits.
Prediction of hydrocarbon extraction from shale requires specialized knowledge of shale play characteristics and analysis to assess effective, economical, and sustainable implementation of oil and natural gas production. In this work, we present a statistical approach that can be used as a preliminary investigation into the hydrocarbon resource potential of a shale play based on limited data. Statistical algorithms for Principal Component Analysis (PCA) and Partial Least Squares Regression (PLS) were used to determine if depositional environments and lithographic boundary characteristics of different plays allowed prediction of specific production parameters. This project characterizes Eagle Ford and Utica formations-two high-producing shale plays in the United States-and Banff/Exshaw and Colorado formations-two recently assessed shale plays in Alberta, Canada. Partial Least Squares Regression models were unable to model gas production parameters from predictor variables, highlighting the complexity of gas formations and the need for data on microscale petrophysical characteristics. In contrast, oil production 1
Paramagnetic molecules offer unique advantages for quantum information science owing to their spatial compactness, synthetic tunability, room-temperature quantum coherence, and potential for optical state initialization and readout. However, current optically addressable molecular qubits are hampered by rapid spin-lattice relaxation (T1) even at sub-liquid nitrogen temperatures. Here we use temperature- and orientation-dependent pulsed electron paramagnetic resonance (EPR) to elucidate the negative sign of the ground-state zero-field splitting (ZFS) and assign T1 anisotropy to specific degrees of freedom in an optically addressable S = 1 Cr(IV) molecular qubit. The anisotropy displays a distinct sin2(2θ) functional form that is not observed in S = ½ Cu(II) or V(IV) microwave addressable molecular qubits. The Cr(IV) T1 anisotropy is ascribed to couplings between electron spins and rotational motion in low-energy acoustic or pseudo-acoustic phonons. Our findings suggest that rotational degrees of freedom should be suppressed to maximize the coherence temperature of optically addressable qubits.
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