scholarly journals Floquet metal-to-insulator phase transitions in semiconductor nanowires

2020 ◽  
Vol 6 (35) ◽  
pp. eaay4922 ◽  
Author(s):  
Iliya Esin ◽  
Mark S. Rudner ◽  
Netanel H. Lindner
Keyword(s):  
Phonon Scattering ◽  
Semiconductor Nanowires ◽  
Steady States ◽  
Electron Hole ◽  
Future Studies ◽  
Density Response Function ◽  
Density Response ◽  
Time Periodic ◽  
Hole Recombination ◽  
Electron Phonon Scattering

We study steady states of semiconductor nanowires subjected to strong resonant time-periodic drives. The steady states arise from the balance between electron-phonon scattering, electron-hole recombination via photoemission, and Auger scattering processes. We show that tuning the strength of the driving field drives a transition between an electron-hole metal (EHM) phase and a Floquet insulator (FI) phase. We study the critical point controlling this transition. The EHM-to-FI transition can be observed by monitoring the presence of peaks in the density-density response function, which are associated with the Fermi momentum of the EHM phase and are absent in the FI phase. Our results may help guide future studies toward inducing exotic nonequilibrium phases of matter by periodic driving.

Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles

1998 ◽  
Vol 536 ◽  
Author(s):  
H. Porteanu ◽  
A. Glozman ◽  
E. Lifshitz ◽  
A. Eychmüller ◽  
H. Weller
Keyword(s):  
Optical Properties ◽  
Magnetic Resonance ◽  
Cds Nanoparticles ◽  
Electron Hole ◽  
Cladding Layer ◽  
Double Beam ◽  
Optically Detected Magnetic Resonance ◽  
Optically Detected ◽  
Cladding Layers ◽  
Hole Recombination

AbstractCdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling

1999 ◽  
Vol 40 (4-5) ◽  
pp. 123-130 ◽  
Author(s):  
S. Malato ◽  
J. Blanco ◽  
C. Richter ◽  
B. Milow ◽  
M. I. Maldonado
Keyword(s):  
Organic Contaminants ◽  
Toxic Waste ◽  
Experimental Plant ◽  
Electron Hole ◽  
Particulate Suspensions ◽  
Photocatalytic System ◽  
Commercial Pesticide ◽  
Pesticide Container ◽  
By Products ◽  
Hole Recombination

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).

scholarly journals When band convergence is not beneficial for thermoelectrics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Junsoo Park ◽  
Maxwell Dylla ◽  
Yi Xia ◽  
Max Wood ◽  
G. Jeffrey Snyder ◽  
...  
Keyword(s):  
Charge Carrier ◽  
First Principles ◽  
Design Principle ◽  
Phonon Scattering ◽  
Charge Carrier Concentration ◽  
Deformation Potential ◽  
Interband Scattering ◽  
Improved Performance ◽  
Full Heusler ◽  
Electron Phonon Scattering

AbstractBand convergence is considered a clear benefit to thermoelectric performance because it increases the charge carrier concentration for a given Fermi level, which typically enhances charge conductivity while preserving the Seebeck coefficient. However, this advantage hinges on the assumption that interband scattering of carriers is weak or insignificant. With first-principles treatment of electron-phonon scattering in the CaMg2Sb2-CaZn2Sb2 Zintl system and full Heusler Sr2SbAu, we demonstrate that the benefit of band convergence can be intrinsically negated by interband scattering depending on the manner in which bands converge. In the Zintl alloy, band convergence does not improve weighted mobility or the density-of-states effective mass. We trace the underlying reason to the fact that the bands converge at a one k-point, which induces strong interband scattering of both the deformation-potential and the polar-optical kinds. The case contrasts with band convergence at distant k-points (as in the full Heusler), which better preserves the single-band scattering behavior thereby successfully leading to improved performance. Therefore, we suggest that band convergence as thermoelectric design principle is best suited to cases in which it occurs at distant k-points.

Sign in / Sign up

Export Citation Format

Share Document