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The present research has been supported by the Institute of Solid State Physics, the University of Latvia within the framework of National Research Program IMIS2. [Grant numbers VPPI IMIS2, IMIS4]. ; The article presents a quantum kinetic framework to study interacting quantum systems. Having the constituting model Hamiltonians of two-band semiconductor and the photoexcited electron-hole pair, their quantum kinetic evolution has been revi-sited. Solution to this nonlinear problem of electron-hole interaction is obtained making use of the self-consistency loop between the densities of photoexcited electrons and holes and the pairwise interaction terms in the constituting model Hamiltonians. In the leading order, this approach supports the required isomorphism between the pairwise interaction and the birth and annihilation operators of the photoexcited electrons and holes as a desirable property. The approach implies the Hilbert space and the tensor product mathematical techniques as an appropriate generalization of the noninteracting electron-hole pair toward several-body systems. ; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²

The primary mechanism governing the emergence of near-room-temperature superconductivity (NRTS) in superhydrides is widely accepted to be the electron-phonon interaction. If so, the temperature-dependent resistance, R(T), in these materials should obey the Bloch-Grüneisen (BG) equation, where the power-law exponent, p, should be equal to the exact integer value of p= 5. However, there is a well-established theoretical result showing that the pure electron-magnon interaction should be manifested by p= 3, and p= 2 is the value for pure electron-electron interaction. Here we aimed to reveal the type of charge carrier interaction in the layered transition metal dichalcogenides PdTe2, high-entropy alloy (ScZrNb)0.65[RhPd]0.35 and highly-compressed elemental boron and superhydrides H3S, LaH x, PrH9 and BaH12 by fitting the temperature-dependent resistance of these materials to the BG equation, where the power-law exponent, p, is a free-fitting parameter. The results showed that the high-entropy alloy (ScZrNb)0.65[RhPd]0.35 exhibited pure electron-phonon mediated superconductivity with p = 4.9 0.4. Unexpectedly, we revealed that all studied superhydrides exhibit 1.8 < p < 3.2. This implies that it is unlikely that the electron-phonon interaction is the primary mechanism for the Cooper pairs formation in highly-compressed superhydrides, and alternative pairing mechanisms, for instance, the electron-magnon, the electron-polaron, the electron-electron and other pairing mechanisms should be considered as the origin for the emergence of NRTS in these compounds. © 2021 IOP Publishing Ltd. ; The author is grateful for financial support provided by the Ministry of Science and Higher Education of Russia (theme 'Pressure' No. AAAA-A18-118020190104-3) and by Act 211 Government of the Russian Federation, Contract No. 02.A03.21.0006.

The problem of conventional, low-temperature superconductivity has been regarded as solved since the seminal work of Bardeen, Cooper, and Schrieffer (BCS) more than 50 years ago. However, the theory does not allow accurate predictions of some of the most fundamental properties of a superconductor, including the superconducting energy gap on the Fermi surface. This thesis describes the development and scientific implementation of a new experimental method that puts this old problem into an entirely new light. The nominee has made major contributions to the development and implementation of a ne.

We present results of measurements and calculations of elastic electron scattering from pyrimidine in the energy range 3-50 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique. The measured cross sections are compared with results of calculations using the well-known Schwinger variational technique and an independent-atom model. Agreement between the measured differential cross sections and the results of the Schwinger calculations is good at lower energies but less satisfactory at higher energies where inelastic channels that should be open are kept closed in the calculations. © 2011 American Physical Society. ; The Support of the Australian Research Council, The International Science Linkage program of the Australian Government, the Spanish Ministerio de Ciencia e Innovacion´ (Project FIS2009-10245), and the EU Framework Programme (COST Action MP1002) is gratefully acknowledged. The work of V.M. and C.W. was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy under Grant No. DE-FG02-97ER14814, and employed the Supercomputing and Visualization Facility at the Jet Propulsion Laboratory. ; Peer Reviewed

We analyze the interaction at the surface of a three-dimensional (3D) topological insulator among 2D electron states belonging to the Dirac cone close to the point of the Brillouin zone and the Rayleigh surface phonon mode. The model deals with an elastic continuum in the long-wavelength limit, in Random Phase Approximation (RPA). Screening of the electronic polarization is quite effective at small wave vectors. On the other hand, the absence of backscattering for the Dirac electrons at the Fermi surface is partly responsible for the reduced influence of the electron-phonon interaction in renormalizing the phonon dispersion at finite wave vectors. We infer that softening of the Rayleigh mode appears as unlikely, at least for the case of a clean and defect-free surface to which our approximate treatment applies. The dielectric response to virtual excitation of the Rayleigh phonon could drive the electron-electron interaction attractive at low frequencies, but the average weak coupling pairing interaction is found to be too small to induce a surface superconducting instability. © 2013 American Physical Society. ; This work was done with financial support from FP7/2007-2013 under Grant No. 264098-MAMA (Multifunctioned Advanced Materials and Nanoscale Phenomena), MIUR-Italy through Prin-Project 2009 "Nanowire high critical temperature superconductor field-effect devices," as well as the Helmholtz Virtual Insitute "New States of Matter." V.P. and F.G. acknowledge financial support from MINECO, Spain, through Grant No. FIS2011-23713, and the European Union, through Grant No. 290846. ; Peer Reviewed

The renormalization function for the electron-phonon interaction is discussed. The system is considered as two-dimensional, and we consider the case of flexural phonons. The flexural phonons have a dispersion which is linear for wave-vectors less than a critical value q꜀ , and quadratic for q > q꜀. The renormalization function differs from the standard expression, and leads to modifications of the normal and superconducting properties of materials.

We present a first principle study of the electron-phonon (e−p) interaction at the Be(0001) surface. The real and imaginary parts of the e−p self-energy (Σ) are calculated for the ¯¯¯Γ surface state in the binding energy range from the ¯¯¯Γ point to the Fermi level. Our calculation shows an overall good agreement with several photoemission data measured at high and low temperatures. Additionally, we show that the energy derivative of ReΣ presents a strong temperature and energy variation close to EF, making it difficult to measure its value just at EF. ; We acknowledge financial support from the Basque Government, the Max Planck Research Award Funds, the Spanish Ministerio de Educacion y Ciencia (MEC), and the Basque Country University. ; Peer reviewed

Microbial electrochemical technologies (METs) are promising for sustainable applications. Recently, electron storage during intermittent operation of electroactive biofilms (EABs) has been shown to play an important role in power output and electron efficiencies. Insights into electron storage mechanisms, and the conditions under which these occur, are essential to improve microbial electrochemical conversions and to optimize biotechnological processes. Here, we discuss the two main mechanisms for electron storage in EABs: storage in the form of reduced redox active components in the electron transport chain and in the form of polymers. We review electron storage in EABs and in other microorganisms and will discuss how the mechanisms of electron storage can be influenced. ; This work is part of the research program Vidi (with project number 17516), which is (partly) financed by the Dutch Research Council (NWO). The research was performed in cooperation with Wetsus, the European Centre of Excellence for Sustainable Water Technology. Wetsus is cofunded by the Dutch Ministry of Economic Affairs and Ministry of Infrastructure and Environment, the European Union Regional Development Fund, the Province of Fryslân, and the Northern Netherlands Provinces. The authors would like to thank the participants of the research theme 'Resource Recovery' for the fruitful discussions and their financial support. The authors also acknowledge the financial support given by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. ...

1 Historical Survey -- 2 Basic Principles of Electron Optics -- 2.1. Rotationally Symmetric Lenses in the Bell-Shaped Field Approximation -- 2.2. Rotationally Symmetric Lenses with Arbitrary Field Distribution -- 2.3. Aberrations Resulting from Misalignment -- 2.4. Multipole Fields for Beam Correction -- 2.5. Image Contrast -- 2.6. Further Sources of Error -- 2.7. Fixed Beam and Scanning Mode -- 3 Superconducting Devices in Electron Microscopy -- 3.1. Advantages of Superconducting Devices -- 3.2. Technical Problems -- 4 Lens Design and Testing -- 4.1. Lens Design and Field Distribution -- 4.2. Correction Systems for Superconducting Objective Lenses -- 4.3. Testing of Objective Lenses -- 5 Systems with Superconducting Lenses -- 5.1. Tested Systems -- 5.2. Projected Systems -- 6 Other Superconducting Elements for Electron Microscopy -- 6.1. Superconducting High-Voltage Beam Generator -- 6.2. Magnetic Dipoles -- 7 Proposed Superconducting 3-MV Microscope -- 7.1. Accelerator -- 7.2. Spectrometer -- 7.3. Microscope Column -- 7.4. Further Improvements of the System -- Appendixes -- A. Superconducting Electron Optical Systems for High-Energy Physics -- A.1. General Remarks -- A.2. Magnet Designs -- B. Application of Electron Microscopy to Basic Research on Superconductivity -- B.1. Imaging by the Decoration Method -- B.2. Imaging by Electron Shadow Microscopy -- B.3. Imaging by an Electron Mirror Microscope -- B.4. Imaging by Lorentz Microscopy -- B.5. Imaging by a Vortex Electron Microscope -- References.