We study an Anderson impurity in a semiconducting host using the density matrix renormalization group technique. We use the U50 one-dimensional Anderson Hamiltonian at half filling as the semiconducting host since it has a hybridization gap. By varying the hybridization of the host, we can control the size of the semiconducting gap D . We consider chains with 25 sites and we place the Anderson ...

In perfect alkali halide crystals only the transverse optic phonons of zero wave vector absorb far infrared radiation in first order. The introduction of impurities in the lattice removes the translational invariance and almost all phonons become optically active. In addition to the absorption at the reststrahlen frequency, impurity induced absorption appears in the phonon band region and somet...

Fertilizer N applied at ever-increasing rates sometimes accumulates in the soil. The practice of fertilizing grain straw with N to stimulate decomposition is questionable, but decomposition of straw immobilizes N that must be compensated for in fertilizing the succeeding crop. Too much N decreases the sucrose content of sugarbeets and decreases sucrose recovery. Experiments were conducted to de...

Nitrogen (N) doping engineering is considered a promising approach to achieve p-type conductivity of Ga2O3 films. However, the defect self-compensation effect has been major obstacle in this field. In work, we propose straightforward and environmentally friendly strategy obtain doped surface on β-Ga2O3 films via nonthermal N plasma-based treatment. By substituting nitrogen with oxygen, acceptor...

Zinc oxide and associated II-VI oxide semiconductor alloys (CdO, MgO, BeO) possess bandgap energies that span the visible and ultraviolet spectral regions, and are of major interest for semiconductor light emitting devices at these wavelengths. The achievement of high quality ZnO substrates and experiments that demonstrate a close lattice match for CdZnO and MgZnO suggest that these materials m...

An HPLC method was employed to create an impurity profile for liguzinediol as an active pharmaceutical ingredient (API), which resulted in the identification of two related impurities. Therefore, in order to improve the quality control of the liguzinediol-API, we identified and then developed a method for quantifying the two impurities (impurity-1 and impurity-2) by LC-TOF-MS-MS and then chemic...

Abstract The “C/O Monitor” for Wendelstein 7-X (W7-X) is a dedicated light impurity XUV spectrometer intended to measure Lyman-α transitions of hydrogen-like ions four low-Z impurities—boron (4.9 nm), carbon (3.4 nitrogen (2.5 nm) and oxygen (1.9 nm). Since the discussed diagnostic will deliver continuous information about line intensities, it crucial understand origin obtained signals with res...

Quantum impurity problems occur in various areas of physics. Some examples are: an impurity spin in a metal (the Kondo problem), the two-impurity Kondo problem, a defect or impurity spin in a spin chain, tunnelling through a barrier in a quantum wire proton-monopole scattering (the Callan-Rubakov effect). Some common features of these problems are: 1. gapless “bulk” excitations (ie. far from th...