Thermal Relaxation in Titanium Nanowires: Signatures of Inelastic Electron-Boundary Scattering in Heat Transfer
We have employed noise thermometry for investigations of thermal relaxation
between the electrons and the substrate in nanowires patterned from 40-nm-thick
titanium film on top of silicon wafers covered by a native oxide. By controlling the
electronic temperature Te by Joule heating at the base temperature of a dilution refrigerator,
we probe the electron–phonon coupling and the thermal boundary resistance at
temperatures Te = 0.5–3 K. Using a regular T 5-dependent electron–phonon coupling
of clean metals and a T 4-dependent interfacial heat flow, we deduce a small contribution
for the direct energy transfer from the titanium electrons to the substrate phonons
due to inelastic electron-boundary scattering.
We study Josephson junctions with weak links consisting of two parallel disordered arms with magnetic properties: ferromagnetic, half-metallic, or normal with magnetic impurities. In the case of long links, the Josephson effect is dominated by mesoscopic fluctuations. In this regime, the system realizes a phi_0 junction with sample-specific phi_0 and critical current. Cooper pair splitting between the two arms plays a major role and leads to 2*Phi_0 periodicity of the current as a function of flux between the arms. We calculate the current and its flux and polarization dependence for the three types of magnetic links.
The Book of Abstracts contains the abstracts of the papers presented at the biannual International Conference “Micro- and Nanoelectronics – 2016” (ICMNE-2016) including the extended Session “Quantum Informatics” (QI-2016). The Conference topics cover the most of the areas dedicated to the physics of integrated micro- and nanoelectronic devices and related micro- and nanotechnologies. The Conference is focused on recent progress in those areas. It continues the series of the AllRussian Conferences (since 1994) and the International Conferences (since 2003).
We develop a theory of the local density of states (LDOS) of disordered superconductors, employing the nonlinear sigma-model formalism and the renormalization-group framework. The theory takes into account the interplay of disorder and interaction couplings in all channels, treating the systems with short-range and Coulomb interactions on equal footing. We explore two-dimensional systems that would be Anderson insulators in the absence of interaction and two- or three-dimensional systems that undergo an Anderson transition in the absence of interaction. We evaluate both the average tunneling density of states and its mesoscopic fluctuations which are related to the LDOS multifractality in normal disordered systems. The obtained average LDOS shows a pronounced depletion around the Fermi energy, both in the metallic phase (i.e., above the superconducting critical temperature) and in the insulating phase near the superconductor-insulator transition (SIT). The fluctuations of the LDOS are found to be particularly strong for the case of short-range interactions, especially, in the regime when transition temperature is enhanced by Anderson localization. On the other hand, the long-range Coulomb repulsion reduces the mesoscopic LDOS fluctuations. However, also in a model with Coulomb interaction, the fluctuations become strong when the systems approach the SIT.
) and in the insulating phase near the superconductor-insulator transition (SIT). The fluctuations of the LDOS are found to be particularly strong for the case of short-range interactions, especially, in the regime when
c is enhanced by Anderson localization. On the other hand, the long-range Coulomb repulsion reduces the mesoscopic LDOS fluctuations. However, also in a model with Coulomb interaction, the fluctuations become strong when the systems approach the SIT.
The future landscape of the micro-nano-electronics will essentially contain extremely miniaturized fully depleted devices such as planar SOI or narrow FinFETs and nanowires. These aspects were covered in both ULIS and EuroSOI conferences, leading to significant overlap. In order to further increase audience and scientific impact, the two sister conferences have decided to merge in 2015.
At ultralow temperatures (T< 100 mK) rather small external disturbance might lead to a noticeable overheating. While electron transport measurements the inevitable external EM noise, picked-up and transmitted through electric wires, results in a mismatch between the electron Te and the phonon Tphtemperatures P~W(Te^5-Tph^5), where P is the power dissipated at the sample with volume W. Hence, for sufficiently small nanoelectronic systems the effect might be clearly pronounced. Multiple methods have been suggested to reduce the undesired electron heating. Typically various RF filters are used to cut the impact of noisy EM environment. Often the supporting amplitude vs. frequency data are obtained only at room temperatures analyzing the impact of 'isolated' elements without taking into consideration the wires. Here we describe the custom made multistage RLC filtering system for ultralow temperature nanoelectronic experiments. The amplitude vs. frequency characteristics were measured down to very low temperatures. Distributed elements theory analysis supports experimental data.
Rapid development of micro- and nanofabrication methods have provoked interest and enabled experimental studies of electronic properties of a vast class of (sub)micrometersize solid state systems. Mesoscopic-size hybrid structures, containing superconducting elements, have become interesting objects for basic research studies and various applications, ranging from medical and astrophysical sensors to quantum computing. One of the most important aspects of physics, governing the behavior of such systems, is the finite concentration of nonequilibrium quasiparticles, present in a superconductor even well below the temperature of superconducting transition. Those nonequilibrium excitations might limit the performance of a variety of superconducting devices, like superconducting qubits, singleelectron turnstiles and microrefrigerators. On the contrary, in some applications, like detectors of electromagnetic radiation, the nonequilibrium state is essential for their operation. It is therefore of vital importance to study the mechanisms of nonequilibrium quasiparticle relaxation in superconductors of mesoscopic dimensions, where the whole structure can be considered as an ‘interface’. At early stages of research the problem was mostly studied in relatively massive systems and at high temperatures close to the critical temperature of a superconductor. We review the recent progress in studies of nonequilibrium quasiparticle relaxation in superconductors including the low temperature limit. We also discuss the open physical questions and perspectives of development in the field.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.