Ultrafast Umklapp-assisted electron-phonon cooling in magic-angle twisted bilayer graphene.

Understanding electron-phonon interactions is fundamentally important and has crucial implications for device applications. However, in twisted bilayer graphene near the magic angle, this understanding is currently lacking. Here, we study electron-phonon coupling using time- and frequency-resolved photovoltage measurements as direct and complementary probes of phonon-mediated hot-electron cooling.

In-patient characteristics of peripheral artery disease in Germany.

Peripheral artery disease (PAD) frequently leads to hospital admission. Sex related differences in in-patient care are a current matter of debate. Data were provided from the German national in-patient sample provided by the Federal Bureau of Statistics (DESTATIS).

A pre-time-zero spatiotemporal microscopy technique for the ultrasensitive determination of the thermal diffusivity of thin films.

Diffusion is one of the most ubiquitous transport phenomena in nature. Experimentally, it can be tracked by following point spreading in space and time. Here, we introduce a spatiotemporal pump-probe microscopy technique that exploits the residual spatial temperature profile obtained through the transient reflectivity when probe pulses arrive before pump pulses.

Milliwatt terahertz harmonic generation from topological insulator metamaterials.

Achieving efficient, high-power harmonic generation in the terahertz spectral domain has technological applications, for example, in sixth generation (6G) communication networks. Massless Dirac fermions possess extremely large terahertz nonlinear susceptibilities and harmonic conversion efficiencies. However, the observed maximum generated harmonic power is limited, because of saturation effects at increasing incident powers, as shown recently for graphene.

Unraveling Heat Transport and Dissipation in Suspended MoSe from Bulk to Monolayer.

Understanding heat flow in layered transition metal dichalcogenide (TMD) crystals is crucial for applications exploiting these materials. Despite significant efforts, several basic thermal transport properties of TMDs are currently not well understood, in particular how transport is affected by material thickness and the material's environment. This combined experimental-theoretical study establishes a unifying physical picture of the intrinsic lattice thermal conductivity of the representative TMD MoSe .

Observation of giant and tunable thermal diffusivity of a Dirac fluid at room temperature.

Conducting materials typically exhibit either diffusive or ballistic charge transport. When electron-electron interactions dominate, a hydrodynamic regime with viscous charge flow emerges. More stringent conditions eventually yield a quantum-critical Dirac-fluid regime, where electronic heat can flow more efficiently than charge.

Hot-Carrier Cooling in High-Quality Graphene Is Intrinsically Limited by Optical Phonons.

Many promising optoelectronic devices, such as broadband photodetectors, nonlinear frequency converters, and building blocks for data communication systems, exploit photoexcited charge carriers in graphene. For these systems, it is essential to understand the relaxation dynamics after photoexcitation. These dynamics contain a sub-100 fs thermalization phase, which occurs through carrier-carrier scattering and leads to a carrier distribution with an elevated temperature.

Out-of-plan pharmacy use: insights into patient behavior.

Objectives: The purpose of this study was to identify and describe patient rationales for filling prescriptions at an out-of-plan pharmacy (OOPP).

Study Design: A cross-sectional survey conducted in February 2013 among a random sample of 1000 patients.

Methods: Adult Kaiser Permanente Colorado (KPCO) patients who had a prescription electronically issued to an OOPP in November 2012 were surveyed.