Engineering topics

Lachinov, A. N.

Publications and source records attributed to Lachinov, A. N..

5 records

DOE OSTI2019

Effect of a Second-Order Phase Transition on the Electrical Conductivity of Metal/Semiconductor Structures

The properties of the Cr–p-Si potential barrier near the temperature of the antiferromagnetic–paramagnetic phase transition in chromium are investigated. A significant change in the potential barrier and an anomalous increase in the conductivity in the Cr–p-Si–Au structure are observed near the temperature of the second-order antiferromagnetic–paramagnetic phase transition in chromium. It is established that current fluctuations in the structure are enhanced when approaching the phase-transition point. The experimental results are interpreted based on the assumption that the observed change in the electron-transport properties of the Cr–Si interface is due to a shift of the Fermi quasi-level in chromium as a result of the second-order phase transition.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2019

Effect of Oxygen on the Conductive Properties of Thin Films of Nonconductive Polymer

The influence of the atmosphere on the electrical conductivity of polydiphenylenephthalide (PDP) films included in the ITO–PDP–Sb sandwich structure is discussed. On the basis of electrophysical measurements and quantum-chemical simulation, a conclusion is drawn that the main contribution to the electrical conductivity of the PDP films comes from oxygen.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Generation and Fragmentation of Phthalide Derivative Negative Ions

Molecules of diphenylphthalide and 3,3-diphenylphthalide-4′,4′-dicarbonic acid have been studied using the method of dissociative electron capture negative ion mass spectrometry. The mean lifetimes of negative molecular ions relative to the electron detachment have been measured. The electron affinity has been estimated in the Arrhenius approximation and calculated by the DFT B3LYP/6-31G+(d) method.

74 ATOMIC AND MOLECULAR PHYSICS↗

DOE OSTI2016

Effect of the nanofilm thickness on the properties of the two-dimensional electron gas at the interface between two dielectrics

The mechanism of formation of the two-dimensional conductivity along the interface between two polymer dielectrics is experimentally studied. The idea of “polar catastrophe,” which was successfully used earlier to explain the electronic properties of the interface between two perovskites LaAlO{sub 3}/SrTiO{sub 3}, is chosen as a base hypothesis. Piezoelectric response microscopy is used to reveal the presence of spontaneous polarization on the surface of a polymer film, and the remanent polarization is found to decrease with increasing film thickness. As in the case of perovskites, the polymer film thickness is found to strongly affect the electrical conductivity along the interface. Substantial differences between these phenomena are detected. The change in the electrical conductivity is shown to be caused by a significant increase in the charge carrier mobility when the film thickness decreases below a certain critical value. The relation between the change in the carrier mobility and the change in the spontaneous surface polarization of the polymer film when its thickness decreases is discussed.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2015

Electron attachment to the phthalide molecule

Phthalide, the simplest chain of conductive polymer thin film, was investigated by means of Electron Transmission Spectroscopy, Negative Ion Mass Spectrometry, and density functional theory quantum chemistry. It has been found that formation of gas-phase long-lived molecular anions of phthalide around 0.7 eV takes place through cleavage of a C–O bond of the pentacyclic ring of the parent molecular anion to give a vibrationally excited (electronically more stable) open-ring molecular anion. The energy of the transition state for ring opening of the parent negative ion is calculated to be 0.65 eV above the neutral ground state of the molecule. The energy (2.64 eV) evaluated for the corresponding transition state in the neutral molecule is much higher, so that the process of electron detachment from the anion must lead to a neutral molecule with its initial pentacyclic structure. The average lifetime of the molecular negative ions formed at an electron energy of 0.75 eV and 80 °C is measured to be about 100 μs. The known switching effect of thin phthalide films could stem from the presence of a similar open/closed transition state also in the polymer.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗