Tunnel diodes utilizing deep-levels in low-temperature-grown (LTG) gallium-arsenide (GaAs) are demonstrated. These tunnel diodes achieve peak-to-valley current ratios as high as 22, a record negative-conductance-per-area of 1/226 Xlm, and a record peak current density of 16 kA/cm, all at room-temperature. 2004 Elsevier Ltd. All rights reserved. PACS: 72.20.H; 73.50.F; 85.30.M; 71.55.E; 73.61.E;...

We demonstrate efficient, error-free 3.125Gb/s modulation of InP-based 1.3μm VCSELs with AsSb-based DBRs up to 60°C. These devices demonstrated high differential efficiencies (>60% at room-temperature), which resulted in a required bias current for modulation of only 5.9mA. The measured extinction ratios were greater than 8dB up to 60°C with a peak-to-peak drive voltage of only 800mV. The 3dB-d...

The vortex dynamics in YBa2Cu3O7−δ thin films have been studied at microwave frequencies. A pronounced peak in the surface resistance, Rs, is observed in these films at frequencies of 4.88 and 9.55 GHz for magnetic fields varying from 0.2 T to 0.8 T. The peak is associated with an order-disorder transformation of the flux line lattice as the temperature or field is increased. The occurrence of ...

In current day microprocessors, exponentially increasing power densities, leakage, cooling costs, and reliability concerns have resulted in temperature becoming a first class design constraint like performance and power. Hence, virtually every high performance microprocessor uses a combination of an elaborate thermal package and some form of Dynamic Thermal Management (DTM) scheme that adaptive...

Experiments were conducted to investigate the effects of low temperatures on anthocyanin accumulation in apple and peach shoots. The anthocyanin concentration in both the apple and peach shoots increased rapidly during cold acclimation reaching the peak value in early December. The anthocyanin might be accumulated in shoots as a result of leucoanthocyanidin conversion. When apple and peach shoo...

The optical conductivity, σ(ω), of the two dimensional one-band Hubbard model is calculated at finite temperature using exact diagonalization techniques on finite clusters. The in-plane d.c. resistivity, ρab, is also evaluated. We find that at large U/t and temperature T, ρab is approximately linear with temperature, in reasonable agreement with experiments on high-Tc superconductors. Moreover,...

We calculate the bulk viscosity of the massive pion gas within unitarized chiral perturbation theory. We obtain a low-temperature peak arising from explicit conformal breaking due to the pion mass and another peak near the critical temperature, dominated by the conformal anomaly through gluon condensate terms. The correlation between bulk viscosity and conformal breaking supports a recent QCD p...

As frequencies and feature size scale faster than operating voltages, power density is increasing in every processor generation. Along with that, leakage (highly dependent on temperature) has become an important source of power. Due to the non uniformity of on-chip power density, localized hot spots may create transient high temperature in a restricted area of the chip. These temperatures are s...

A prominent peak in the electron temperature of the topside ionosphere is observed beneath the magnetospheric cleft. The present study uses DE-2 data obtained in the Northern Winter Hemisphere to investigate this phenomenon. First, the dependence of the location and magnitude of the temperature peak on the magnetic activity is determined. Next, using a superposed epoch analysis, the mean latitu...

We present experimental results of transverse electron-focusing measurements performed using n-type GaAs. In the presence of a small transverse magnetic field (B⊥), electrons are focused from the injector to detector leading to focusing peaks periodic in B⊥. We show that the odd-focusing peaks exhibit a split, where each sub-peak represents a population of a particular spin branch emanating fro...