Kavli Affiliate: Brad Ramshaw | Summary:Superconductivity in three dimensions is almost universally governed by Ginzburg-Landau mean field theory, with critical fluctuations typically confined to within a few percent of the transition temperature ($T_rm c$). We report that the heavy-Fermion superconductor UTe$_2$ exhibits a fluctuation regime that extends over a temperature range as wide as $T_rm […]

Kavli Affiliate: Darrell Schlom | Summary:Tantalum dioxide (TaO2) is a metastable tantalum compound. Here, we report the epitaxial stabilization of TaO2 on Al2O3 (1-102) (r-plane sapphire) substrates using suboxide molecular-beam epitaxy (MBE) and thermal laser epitaxy (TLE), demonstrating single-oriented, monodomain growth of anisotropically strained thin films. Microstructural investigation is performed using synchrotron X-ray diffraction and […]

Kavli Affiliate: David Muller | Summary:Tantalum dioxide (TaO2) is a metastable tantalum compound. Here, we report the epitaxial stabilization of TaO2 on Al2O3 (1-102) (r-plane sapphire) substrates using suboxide molecular-beam epitaxy (MBE) and thermal laser epitaxy (TLE), demonstrating single-oriented, monodomain growth of anisotropically strained thin films. Microstructural investigation is performed using synchrotron X-ray diffraction and […]

Kavli Affiliate: Grace Xing | Summary:AlYN and AlScN have recently emerged as promising nitride materials that can be integrated with GaN to form two-dimensional electron gases (2DEGs) at heterojunctions. Electron transport properties in these heterostructures have been enhanced through careful design and optimization of epitaxial growth conditions. In this work, we report for the first […]

Kavli Affiliate: Grace Xing | Summary:UV-C LEDs pseudomorphically grown by MBE on bulk AlN substrates emitting at 265 nm are demonstrated. High current density up to 800 A/cm$^2$, 5 orders of on/off ratio, and low differential on-resistance of 2.6 m$Ωcdot$cm$^2$ at the highest current density is achieved. The LED heterostructure has a high refractive index […]

Kavli Affiliate: David Muller | Summary:Animated characters often move in non-physical ways and have proportions that are far from a typical walking robot. This provides an ideal platform for innovation in both mechanical design and stylized motion control. In this paper, we bring Olaf to life in the physical world, relying on reinforcement learning guided […]

Kavli Affiliate: Debanjan Chowdhury | Summary:The observation of Planckian scattering, often inferred from Drude fits in strongly correlated metals, raises the question of how to extract an intrinsic timescale from measurable quantities in a model-independent way. We address this by focusing on a ratio ($calB$) of spectral moments of the dissipative part of the optical […]

Kavli Affiliate: Grace Xing | Summary:Ohmic contacts to high (>70%) Al content n-type Al$_x$Ga$_1-x$N ultra-wide bandgap semiconductor layers in nitride electronic and photonic devices are typically fabricated by a lift-off process and high temperature ($>700^circ$C) thermal alloying. These conditions often result in significant structural deformations of the fabricated structures and impose a harsh thermal budget […]

Kavli Affiliate: Debanjan Chowdhury | Summary:Two-dimensional transition metal dichalcogenide (TMD) semiconductors exhibit a wide range of novel phenomena at millielectronvolt (terahertz-frequency) energy scales, including superconducting and correlation-induced insulating gaps that are frequently accompanied by symmetry breaking. However, due to the subwavelength dimensions and the often low conductivities of these systems, their intrinsic THz plasmons and […]

Kavli Affiliate: Grace Xing | Summary:We report the structural and electronic properties of niobium nitride (NbN) thin films grown by molecular beam epitaxy on c-plane sapphire with miscut angles of $0.5^texto$, $2^texto$, $4^texto$, and $10^texto$ towards m-axis. X-ray diffraction (XRD) scans reveal that the full width at half maximum of the rocking curves around the […]