Galvano-dipolar effect

The phenomenology of the photogalvanic effect permits prediction of a number of physical phenomena, the most interesting of which is the galvano-dipolar effect. This effect consists in the appearance of an electric dipole moment in a sample through which an electric current is passed. A possible microscopic mechanism of this phenomenon, which can be realized in centrosymmetric media as well, is considered.     

Quantum Nernst effect

It is theoretically predicted that the Nernst coefficient is strongly suppressed and the thermal conductance is quantized in the quantum Hall regime of the two-dimensional electron gas. The Nernst effect is the induction of a thermomagnetic electromotive force in the y-direction under a temperature bias in the x-direction and a magnetic field in the z-direction. The quantum nature of the Nernst effect is analyzed with the use of a circulating edge current and is demonstrated numerically. The present system is a physical realization of the non-equilibrium steady state.     

Valley Hall effect and Nernst effect in strain engineered graphene

We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.     

关于焦耳效应和焦-汤效应的比较

给出了焦耳效应和焦耳-汤姆孙效应的比较方法，对焦-汤实验容易得到与理想气体有差别的结果而焦耳实验却不容易得到这种结果的原因进行了诠释，并对有关章的结论提出了商榷意见。     

Tunneling hall effect

Electron tunneling in a semiconductor heterostructure with a barrier in a weak magnetic field applied parallel to the barrier interfaces is analyzed theoretically. A novel mechanism of the Hall effect in this structure is suggested. It is shown that the Hall current near the sufficiently wide barrier is determined by the orbital effect of the magnetic field on the electron motion under the barrier, rather than by the electron {ie778-1}-drift and scattering in the conductive regions lying to the left and to the right of the barrier.     

Photonic flame effect

The results of study of the photonic flame effect observed in photonic crystals and nanocomposites based on opal matrixes are presented. The effect has been discovered recently [1] and manifests itself as radiation with duration of a few seconds in the blue-green spectral region under excitation by pulsed laser light with a wavelength of 694.3 nm and a pulse duration of 20 ns.     

Space charge effect and mirror charge effect in photoemission spectroscopy

We report the observation and systematic investigation of the space charge effect and mirror charge effect in photoemission spectroscopy. When pulsed light is incident on a sample, the photo-emitted electrons experience energy redistribution after escaping from the surface because of the Coulomb interaction between them (space charge effect) and between photo-emitted electrons and the distribution of mirror charges in the sample (mirror charge effect). These combined Coulomb interaction effects give rise to an energy shift and a broadening which can be on the order of 10 meV for a typical third-generation synchrotron light source. This value is comparable to many fundamental physical parameters actively studied by photoemission spectroscopy and should be taken seriously in interpreting photoemission data and in designing next generation experiments.     

Giant photovoltaic effect

A giant photovoltaic effect was revealed in silicon-type photoelectronic converters (solar cells) coated with specific antireflecting films developed by our research group. More specifically, it was found that the ratio of photoconversion efficiency for a solar cell with such an antireflective film on its surface to the efficiency for a solar cell without the film equals a second power of relation of photoelectromotive force of a converter with the film to the photoelectromotive force of a converter without the film. The film comprises an antireflecting coating that is high-efficient in the wavelength range of 450 to 1000 nm and that is synthesized on the basis of novel nanomaterials that provide the quasi-zero average complex refractive index of nanocomposite film.     

Radiation piezoelectric effect

The results of experimental investigation of a new phenomenon - appearance of an emf across a single germanium sample subject both to irradiation with charged particles and to uniaxial deformation in a direction perpendicular to the particle beam (radiation piezoelectric effect - RPE) - are reported.     

Generalized sagnac effect

Experiments were conducted to study light propagation in a light waveguide loop consisting of linearly and circularly moving segments. We found that any segment of the loop contributes to the total phase difference between two counterpropagating light beams in the loop. The contribution is proportional to a product of the moving velocity v and the projection of the segment length Delta(l) on the moving direction, Deltaphi=4piv x Delta(l)/c(lambda). It is independent of the type of motion and the refractive index of waveguides. The finding includes the Sagnac effect of rotation as a special case and suggests a new fiber optic sensor for measuring linear motion with nanoscale sensitivity.     

Aharonov-Bohm effect revisited

The Aharonov-Bohm (AB) effect shows that electromagnetic potentials can influence an electron in a field-free region. The single-slit and double-slit electron diffraction patterns are explicitly calculated here by the Feynman path integral method for different configurations of the magnetic field in order to compare the effect of the vector potential with the effect of the magnetic field. When an electron passes through a magnetic field behind the slits, the whole diffrection pattern is shifted due to the Lorentz force. When an electron passes through two slits with magnetic flux confined to a small cylinder between them, the double-slit diffraction pattern is shifted within the single-slit diffraction envelope. The asymmetric diffraction pattern corresponds to a nonzero average displacement and momentum of the electron even though the field exerts no force on the electron. This behavior can be understood on the basis of a quantum-mechanical interference effect. The classical limit of the electron diffraction patterns is taken to obtain the classical particle distributions. The effect of the potential vanishes in the classical limit, while the effect of the magnetic field persists because of the Lorentz force.     

Plasmonic Dicke effect

We study cooperative emission by an ensemble of emitters, such as fluorescing molecules or semiconductor quantum dots, near a metal nanoparticle. The primary mechanism of cooperative emission is resonant energy transfer between emitters and plasmons rather than Dicke radiative coupling between emitters. The emission is dominated by three superradiant states with the same quantum yield as a single emitter, leading to a drastic reduction of ensemble radiated energy down to just thrice of that by a single emitter, the remaining energy being dissipated in the metal through subradiant states. We perform numerical calculations of system eigenstates and find that the plasmonic Dicke effect interactions affect is not impacted by the interactions between emitters or non-radiative losses in the metal.     

The photo-neutronrefractive effect

Since its discovery in 1966, the photorefractive effect, i.e. the change of the refractive index upon illumination with light, has been studied extensively in various materials and has turned out to play a key role in modern optical technologies like photonics. This article focuses on substances that change their refractive index for neutrons when irradiated with light. In analogy to light optics, we call them photo-neutronrefractive. After a short introduction to the relevant concepts of neutron optics, two materials exhibiting this effect, a photopolymer and an electrooptic crystal, are presented. Further, we discuss the progress made concerning the development of creating light-induced gratings for neutron diffraction, which culminated in the setup of an interferometer for cold neutrons. Experiments performed on photo-neutronrefractive materials are surveyed and the variety of corresponding results obtained is presented, including a discussion of their impact on material science, neutron optics, and the foundations of physics. Received: 23 July 2002 / Published online: 25 October 2002 RID="*" ID="*"Corresponding author. Fax: +43-1/4277-9511, E-mail: martin.fally@exp.univie.ac.at     

Thermal Hall-Senftleben effect

A new effect is predicted, namely, the occurrence of a heat flow perpendicular to both the temperature gradient and the magnetic field in solid dielectrics with unfrozen rotational degrees of freedom of molecules. The method of moments is developed with allowance made for the processes of phonon scattering by molecules with a change in their rotational state.     

Spin-asymmetric Josephson effect

We propose that with ultracold Fermi gases one can realize a spin-asymmetric Josephson effect in which the two spin components of a Cooper pair are driven asymmetrically--corresponding to driving a Josephson junction of two superconductors with different voltages V(↑) and V(↓) for spin up and down electrons, respectively. We predict that the spin up and down components oscillate at the same frequency but with different amplitudes. Furthermore our results reveal that the standard interpretation of the Josephson supercurrent in terms of coherent bosonic pair tunneling is insufficient. We provide an intuitive interpretation of the Josephson supercurrent as interference in Rabi oscillations of pairs and single particles, the latter causing the asymmetry.     

Photonic flame effect

We observed a new effect which we called the photonic flame effect (PFE). Several three-dimensional photonic crystals (synthetic opals) were posed on a Cu plate at the temperature of liquid nitrogen (77 K). The typical distance between the crystals was 1–5 cm. A long-continued optical luminescence was excited in one of the crystals by the ruby laser pulse. A visible luminescence appeared in the other crystals (not illuminated by the laser pulse), with a time delay with respect to the luminescence in the first crystal (illuminated by the laser pulse) being observed. We examined synthetic opal crystals and those filled with nonlinear liquids.     

The becquerel effect

It is shown that the Becquerel effect (the photogalvanic effect) consists of an effect analogous to the Dember effect in semiconductors combined with the appearance of a photo-emf, accompanied by a photoadsorption effect at the electrode surfaces.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 8, pp. 104–107, August, 1969.     

Lorentz effect imaging

This paper presents a method that can detect minute electrical activity in a strong magnetic field. It uses displacement encoding to detect small spatial displacement induced by Lorentz force on the conducting materials, hence the term Lorentz effect imaging (LEI). With increased sensitivity from improved hardware capabilities or signal averaging, this technique may be used to detect spatial displacements induced by small currents comparable to neuronal electrical current. The initial results using the LEI technique may provide insight in assessing the feasibility of using MRI to non-invasively detect the neuronal electrical activities.     

The casimir effect as a screening effect in quantized field theory

We study the vacuum energy and the vacuum force in a system of quantized scalar fields (massive and massless) in interaction with a given screening medium. Regularization of the energy is studied and the types of determinable forces are clarified. The Casimir effect—the attraction between two conducting plates in a vacuum, and its extension to different geometries —is re-examined in this framework. Instead of the puzzling repulsion for a spherical shell conductor, an attractive force is obtained in our case. As a by-product, we obtain a potential energy between two balls of large screening power and at remote distance R, ?a₁a₂/4πR³, where a_i are the ball radii.     

Relativistic Hall effect

We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin-Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices and mechanical flywheels and also discuss various fundamental aspects of this phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales, from elementary spinning particles, through classical light, to rotating black holes.