Cable bacteria delay euxinia and modulate phosphorus release in coastal hypoxic systems

Cable bacteria are long, filamentous bacteria with a unique metabolism involving centimetre-scale electron transport. They are widespread in the sediment of seasonally hypoxic systems and their metabolic activity stimulates the dissolution of iron sulfides (FeS), releasing large quantities of ferrous iron (Fe²⁺) into the pore water...

System Merits or Failures?: Policies for Transition to Sustainable P and N Systems in The Netherlands and Finland

Nitrogen (N) and phosphorus (P) cycles are absolutely vital in maintaining sustainable food systems. Human activities disturb the natural balance of these cycles by creating enormous additional nutrient fluxes, causing eutrophication of waterways and pollution in land systems. To tackle this problem, sustainable nutrient management is required....

Transport through a single donor in p-type silicon

Single phosphorus donors in silicon are promising candidates as qubits in the solid state. Here, we present low temperature scanning probe microscopy and spectroscopy measurements of individual phosphorus dopants deliberately placed in p-type silicon ?1?nm below the surface. The ability to image individual dopants combined with scanning...

Terahertz Raman laser based on silicon doped with phosphorus

Raman-type stimulated emission at frequencies between 5.0 and 5.2?THz as well as between 6.1 and 6.4?THz has been realized in silicon crystals doped by phosphorus donors. The Raman laser operates at around 5?K under optical excitation by a pulsed, frequency-tunable infrared free electron laser. The frequencies of the observed laser emission are...

Terahertz gain on shallow donor transitions in silicon

Small signal gain measurements of optically excited terahertz silicon lasers are reported. Two types of lasers, Si:P and Si:Bi, were investigated. They were optically excited with radiation from a free electron laser or a CO2 laser. The experiments were performed with an oscillator-amplifier scheme where one sample serves as a laser while the...

Stimulated terahertz emission from group-V donors in silicon under intracenter photoexcitation

Frequency-tunable radiation from the free electron laser FELIX was used to excite neutral phosphorus and bismuth donors embedded in bulk monocrystalline silicon. Lasing at terahertz frequencies has been observed at liquid helium temperature while resonant pumping of odd parity impurity states. The threshold was about two orders of magnitude...