Lead-free, silicon compatible materials showing large electromechanical responses comparable to, or better than conventional relaxor ferroelectrics, are desirable for various nanoelectromechanical devices and applications. Defect-engineered electrostriction has recently been gaining popularity to obtain enhanced electromechanical responses at sub 100 Hz frequencies. Here, we report record values of electrostrictive strain coefficients (M) at frequencies as large as 5 kHz (1.
View Article and Find Full Text PDFWe provide an algorithm, i-SPin 2, for evolving general spin-s Gross-Pitaevskii or nonlinear Schrödinger systems carrying a variety of interactions, where the 2s+1 components of the "spinor" field represent the different spin-multiplicity states. We consider many nonrelativistic interactions up to quartic order in the Schrödinger field (both short and long range, and spin-dependent and spin-independent interactions), including explicit spin-orbit couplings. The algorithm allows for spatially varying external and/or self-generated vector potentials that couple to the spin density of the field.
View Article and Find Full Text PDFPerfectly vertical grating couplers have various applications in optical I/O such as connector design, coupling to multicore optical fibers and multilayer silicon photonics. However, it is challenging to achieve perfectly vertical coupling without simultaneously increasing reflection. In this paper, we use the adjoint method as well as an adjoint-inspired methodology to design devices that can be fabricated using only a single-etch step in a c-Si 193 nm DUV immersion lithography process, while maintaining good coupling and low reflection.
View Article and Find Full Text PDFIntroduction: Catheter-based treatment of atrial fibrillation (AF) requires the isolation of the triggering foci as well as modification of the atria with substrate that sustains AF. The creation of linear lesions in the left atrium with standard radiofrequency ablative methods requires long procedural times with unpredictable results.
Methods: The simultaneous delivery of phase-shifted radiofrequency energy from a multipolar catheter was compared to the conventional drag-and-burn technique for creating linear lesions in 10 dogs.