Theory of free-carrier absorption in the presence of a quantizing magnetic field in quasi-one-dimensional quantum well structures

The theory of free-carrier absorption is given for a quasi one-dimensional semiconducting structures in a quantizing magnetic field for the case when carriers are scattered by polar optical phonons and acoustic phonons and the radiation field is polarized perpendicular to the magnetic field direction

Optical intersubband transitions in quantum wires with an applied magnetic field

The intersubband optical absorption is investigated in parabolic quantum wires in the presence of a tilted magnetic fields. We show that for increasing magnetic field the intersubband absorption peak is shifted to higher energies and its amplitude is increased, too. In particular, it has been shown that the direction of the magnetic field plays a significant role in the intersubband optical absorption

Interface roughness induced intrasubband scattering in a quantum well under an electric field

Scattering rates in the lowest subband in a quantum well are calculated for interface roughness scattering when an electric field is applied normally to the layer plane. It is found that the interface roughness scattering rate increases with increasing electric field. The electric field changes the interface roughness scattering rates drastically in thick QWs as compared with those for the zero-field case

Confined LO phonon limited free carrier absorption in quantum well wires

The theory of free-carrier absorption is given for quantum well wire for the case where the carriers are scattered by confined longitudinal-optical (LO) phonons and the radiation field is polarized along the length of the wire. Both the multisubband structure and confined phonon modes are considered together. The free carrier absorption coefficients are calculated taking into account all possible LO phonon modes as well as all possible electron intersubband transitions. The results show that the absorption coefficient decreases with increasing the photon frequency and decreases with temperature. It was found that in quantum wire the electron-optic phonon interaction give a greater contribution to the absorption than the electron-confined LO phonon interaction. The results are interpreted in terms of confined LO phonons-assisted transitions between size quantized subbands

Theory of the free-carrier absorption in quantum wires with boundary roughness scattering

A theory of free carrier absorption is given for quantum wires when carriers are scattered by boundary roughness and the radiation field is polarized along the length of the wire. The free-carrier absorption coefficient is found to be an oscillatory function of the photon frequency and of the wire width. The obtained results are compared with different scattering mechanisms for quasi-one-dimensional structures. It is found that boundary roughness scattering is important especially when the wire width and temperature decreases. In addition, it was found that in quantum wire the electron - boundary roughness interaction gives a greater contribution to the absorption than the electron-acoustic phonon interaction. The results are interpreted in terms of boundary roughness-assisted transitions between size quantized subbands

Alloy scattering in quantum well wire structures of semiconductor ternaries

We studied the effect of the alloy-disorder-scattering on the electron transport in a quasi-one-dimensional semiconductor. Performed were analytical calculations of the alloy-disorder-limited momentum relaxation time for carrier scattering in a cylindrical quantum wire using modeling wave functions, when the transverse part of the carrier wave function is taken as a Bessel function. It is found that the one-dimensional mobility is significantly greater than two-dimensional one. It is shown that the alloy-disorder-scattering-limited mobility increases with the increasing wire radius and increases with the increasing temperature. We compare our results with different scattering mechanisms for one-dimensional systems. Results are also included for the alloy composition dependence of the mobility

The ATLAS experiment at the CERN Large Hadron Collider: a description of the detector configuration for Run 3

The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 of the LHC, a luminosity of ℒ = 2 × 1034 cm-2 s-1 was routinely achieved at the start of fills, twice the design luminosity. For Run 3, accelerator improvements, notably luminosity levelling, allow sustained running at an instantaneous luminosity of ℒ = 2 × 1034 cm-2 s-1, with an average of up to 60 interactions per bunch crossing. The ATLAS detector has been upgraded to recover Run 1 single-lepton trigger thresholds while operating comfortably under Run 3 sustained pileup conditions. A fourth pixel layer 3.3 cm from the beam axis was added before Run 2 to improve vertex reconstruction and b-tagging performance. New Liquid Argon Calorimeter digital trigger electronics, with corresponding upgrades to the Trigger and Data Acquisition system, take advantage of a factor of 10 finer granularity to improve triggering on electrons, photons, taus, and hadronic signatures through increased pileup rejection. The inner muon endcap wheels were replaced by New Small Wheels with Micromegas and small-strip Thin Gap Chamber detectors, providing both precision tracking and Level-1 Muon trigger functionality. Trigger coverage of the inner barrel muon layer near one endcap region was augmented with modules integrating new thin-gap resistive plate chambers and smaller-diameter drift-tube chambers. Tile Calorimeter scintillation counters were added to improve electron energy resolution and background rejection. Upgrades to Minimum Bias Trigger Scintillators and Forward Detectors improve luminosity monitoring and enable total proton-proton cross section, diffractive physics, and heavy ion measurements. These upgrades are all compatible with operation in the much harsher environment anticipated after the High-Luminosity upgrade of the LHC and are the first steps towards preparing ATLAS for the High-Luminosity upgrade of the LHC. This paper describes the Run 3 configuration of the ATLAS detector