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Of all publications in the section: 28
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Article
Smirnov I. S., Novoselova E., Kondrashov P. et al. Applied Physics Letters. 1996. Vol. 69. No. 3. P. 305-307.
Added: Mar 19, 2013
Article
Omelchenko A., Zhukov A., Maksimov M. et al. Applied Physics Letters. 2013. Vol. 102. P. 112101.

We introduce an analytical approach to describe the multi-state lasing phenomenon in quantum dot lasers. We show that the key parameter is the hole-to-electron capture rate ratio. If it is lower than a certain critical value, the complete quenching of ground-state lasing takes place at high injection levels. At higher values of the ratio, the model predicts saturation of the ground-state power. This explains the diversity of experimental results and their contradiction to the conventional rate equation model. Recently found enhancement of ground-state lasing in p-doped samples and temperature dependence of the ground-statepower are also discussed.

Added: Sep 17, 2018
Article
A. A. Melnikov, A. A. Sokolik, Frolov A. V. et al. Applied Physics Letters. 2019. Vol. 114. P. 191107-1-191107-5.

We have measured the ultrafast anisotropic optical response of highly doped graphene to an intense single cycle terahertz pulse. The time profile of the terahertz-induced anisotropy signal at 800 nm has minima and maxima repeating those of the pump terahertz electric field modulus. It grows with increasing carrier density and demonstrates a specific nonlinear dependence on the electric field strength. To describe the signal, we have developed a theoretical model that is based on the energy and momentum balance equations and takes into account optical phonons of graphene and the substrate. According to the theory, the anisotropic response is caused by the displacement of the electronic momentum distribution from zero momentum induced by the pump electric field in combination with polarization dependence of the matrix elements of interband optical transitions.

Added: May 21, 2019
Article
Shapiro Dmitriy S. Applied Physics Letters. 2017. Vol. 111. No. 25. P. 251601-1-251601-5.

The influence of individual impurities of Fe on the electronic properties of topological insulator Bi2Se3 is studied by Scanning Tunneling Microscopy. The microscope tip is used in order to remotely charge/discharge Fe impurities. The charging process is shown to depend on the impurity location in the crystallographic unit cell, on the presence of other Fe impurities in the close vicinity, and on the overall doping level of the crystal. We present a qualitative explanation of the observed phenomena in terms of tip-induced local band bending. Our observations evidence that the specific impurity neighborhood and the position of the Fermi energy with respect to both the Dirac point and bulk bands have to be taken into account when considering the electron scattering on the disorder in topological insulators.

Added: Feb 8, 2019
Article
Kawabata S., Ozaeta A., Vasenko A.S. et al. Applied Physics Letters. 2013. Vol. 103. P. 032602-1-032602-1.

Efficient electron-refrigeration based on a normal-metal/spin-filter/superconductor junction is proposed and demonstrated theoretically. The spin-filtering effect leads to values of the cooling power much higher than in conventional normal-metal/nonmagnetic-insulator/superconductor coolers and allows for an efficient extraction of heat from the normal metal. We demonstrate that highly efficient cooling can be realized in both ballistic and diffusive multi-channel junctions in which the reduction of the electron temperature from 300 mK to around 50 mK can be achieved. Our results indicate the practical usefulness of spin-filters for efficiently cooling detectors, sensors, and quantum devices.

Added: Sep 28, 2015
Article
Дурнев М. В., Manca M., Wang G. et al. Applied Physics Letters. 2018. Vol. 112. No. 14. P. 1-5.

In III–V semiconductor nano-structures, the electron and nuclear spin dynamics are strongly coupled. Both spin systems can be controlled optically. The nuclear spin dynamics are widely studied, but little is known about the initialization mechanisms. Here, we investigate optical pumping of carrier and nuclear spins in charge tunable GaAs dots grown on 111A substrates. We demonstrate dynamic nuclear polarization (DNP) at zero magnetic field in a single quantum dot for the positively charged exciton X+ state transition. We tune the DNP in both amplitude and sign by variation of an applied bias voltage Vg. Variation of ΔVg on the order of 100 mV changes the Overhauser splitting (nuclear spin polarization) from −30 μeV (−22%) to +10 μeV (+7%) although the X+ photoluminescence polarization does not change sign over this voltage range. This indicates that absorption in the structure and energy relaxation towards the X+ ground state might provide favourable scenarios for efficient electron-nuclear spin flip-flops, generating DNP during the first tens of ps of the X+ lifetime which is on the order of hundreds of ps. Voltage control of DNP is further confirmed in Hanle experiments.

We acknowledge funding from ERC Grant No. 306719, Marie Sklodowska-Curie actions ITN Spin-NANO No. 676108 and ITN 4PHOTON No. 721394 and LIA CNRS—Ioffe RAS ILNACS, and RFBR Grant No. 17-52-16020. M.V.D. acknowledges financial support from the RFBR project No. 16-32-60175. We thank JSPS Kakenhi No. 16H02203 and ATLA, Japan.

Added: Nov 11, 2020
Article
Shchepetilnikov A., Frolov D., Solovyev V. et al. Applied Physics Letters. 2018. Vol. 113. No. 5. P. 052102-052102.

Spin resonance of a two-dimensional electron system confined in a GaN/AlGaN heterostructure grown by molecular beam epitaxy was resistively detected over a wide range of magnetic field and microwave frequency. Although the spin-orbit interaction is strong in this type of heterostructure at zero magnetic field, surprisingly the width of the detected spin resonance line was very narrow— down to 6.5 mT at 13.3 T. The spin depolarization time extracted from the resonance linewidth was estimated to be 2 ns. The electron g-factor was measured with high accuracy, resembling a value close to the free-electron value and its dependence on the magnetic field was studied.

Added: Nov 25, 2018
Article
Omelchenko A., Durnev M., Yakovlev E. et al. Applied Physics Letters. 2010. Vol. 97. No. 5. P. 051904.

Indium incorporation into strained InGaN coherently grown on a GaN substrate with arbitrary polarity is simulated using a simplified epitaxy model. The InGaN composition is predicted as a function of C-axis inclination angle. Effect of strain originated from the lattice mismatch on optical transitions in the bulk InGaN and quantum wells is examined with account of both complex valence band structure and polarization charges induced at the InGaN/GaN interfaces. A higher indium incorporation on nonpolar and semipolar planes, as compared to the ordinary C-plane, is found to not necessarily result in a longer emission wavelength.

Added: Sep 17, 2018
Article
Curran P., Kim J., Satchell N. et al. Applied Physics Letters. 2015. Vol. 107. P. 262602-262602.

We demonstrate that the magnetic state of a superconducting spin valve, that is normally controlled with an external magnetic field, can also be manipulated by varying the temperature which increases the functionality and flexibility of such structures as switching elements. In this case, switching is driven by changes in the magnetostatic energy due to spontaneous Meissner screening currents forming in the superconductor below the critical temperature. Our scanning Hall probe measurements also reveal vortex-mediated pinning of the ferromagnetic domain structure due to the pinning of quantized stray fields in the adjacent superconductor. The ability to use temperature as well as magnetic field to control the local magnetisation structure raises the prospect of potential applications in magnetic memory devices.

Added: Feb 22, 2017
Article
Soloviev I., Klenov N., Bakurskiy S. et al. Applied Physics Letters. 2014. Vol. 105. P. 242601.

We propose a control element for a Josephson spin valve. It is a complex Josephson device containing ferromagnetic (F) layer in the weak-link area consisting of two regions, representing 0 and π Josephson junctions, respectively. The valve's state is defined by mutual orientations of the F-layer magnetization vector and boundary line between 0 and π sections of the device. We consider possible implementation of the control element by introduction of a thin normal metal layer in a part of the device area. By means of theoretical simulations, we study properties of the valve's structure as well as its operation, revealing such advantages as simplicity of control, high characteristic frequency, and good legibility of the basic states.

Added: Oct 23, 2016
Article
Gevorkian Z., Gasparian V., Yurii Lozovik. Applied Physics Letters. 2016. Vol. 108. P. 051109.

Solar cells based on organometal halide perovskites have recently become very promising among other materials because of their cost-effective character and improvements in efficiency. Such performance is primarily associated with effective light absorption and large diffusion length of charge carriers. Our paper is devoted to the explanation of large diffusion lengths in these systems. The transport mean free path of charged carriers in a perovskite/TiO2heterojunction that is an important constituent of the solar cells have been analyzed. Large transport length is explained by the planar diffusion of indirect excitons.Diffusion length of the coupled system increases by several orders compared to single carrier length due to the correlated character of the effective field acting on the exciton.

Added: Oct 18, 2016
Article
Kugel K., Kovaleva N., Chvostova D. et al. Applied Physics Letters. 2017. Vol. 111. No. 18. P. 183104-1-183104-5.
Using dc transport and wide-band spectroscopic ellipsometry techniques, we study localization effects in the disordered  metallic Ta interlayer of different thicknesses in the multilayer films (MLFs) (Ta–FeNi)N grown by rf sputtering deposition. In the grown MLFs, the FeNi layer was 0.52 nm thick, while the Ta layer thickness varied between 1.2 and 4.6 nm. The Ta layer dielectric function was extracted from the Drude-Lorentz simulation. The dc transport study of the MLFs implies non-metallic ðdq=dT < 0Þ behavior, with negative temperature coefficient of resistivity (TCR). The TCR absolute value increases upon increasing the Ta interlayer thickness, indicating enhanced electron localization. With that, the free charge carrier Drude response decreases. Moreover, the pronounced changes occur in the extended spectral range, involving the higher energy Lorentz bands. The Drude dc conductivity drops below the weak localization limit for the thick Ta layer. The global band structure reconstruction may indicate the formation of a nearly localized many-body electron state.
Added: Jan 29, 2018
Article
Tretyakov I., Ryabchun S., Finkel M. et al. Applied Physics Letters. 2011. Vol. 98. No. 3. P. 033507.

We report a record double sideband noise temperature of 600 K (5h/ k B) offered by a NbN hot-electron bolometer receiver at 2.5 THz. Allowing for standing wave effects, this value was found to be constant in the intermediate frequency range 1-7 GHz, which indicates that the mixer has an unprecedentedly large noise bandwidth in excess of 7 GHz. The insight into this is provided by gain bandwidth measurements performed at the superconducting transition. They show that the dependence of the bandwidth on the mixer length follows the model for an HEB mixer with diffusion and phonon cooling of the hot electrons.

Added: Jul 1, 2014
Article
Shcherbatenko M., Tretyakov I., Lobanov Y. et al. Applied Physics Letters. 2016. Vol. 109. No. 13. P. 132602-1-132602-4.

We present a physically consistent interpretation of the dc electrical properties of niobiumnitride (NbN)-based superconducting hot-electron bolometer mixers, using concepts of nonequilibrium superconductivity. Through this, we clarify what physical information can be extracted from the resistive transition and the dc current-voltage characteristics, measured at suitably chosen temperatures, and relevant for device characterization and optimization. We point out that the intrinsic spatial variation of the electronic properties of disordered superconductors, such as NbN, leads to a variation from device to device

Added: Oct 20, 2016
Article
Ohene Y., Marinov Ilya, de Laulanie L. et al. Applied Physics Letters. 2015. Vol. 106. No. 23. P. 1-5.

Phase images of biological specimens were obtained by the method of Quadriwave Lateral Shearing Interferometry (QWLSI). The QWLSI technique produces, at high resolution, phase images of the cells having been exposed to a plasma treatment and enables the quantitative analysis of the changes in the surface area of the cells over time. Morphological changes in the HTori normal thyroid cells were demonstrated using this method. There was a comparison of the cell behaviour between control cells, cells treated by plasma of a nanosecond dielectric barrier discharge, including cells pre-treated by catalase, and cells treated with an equivalent amount of H2O2. The major changes in the cell membrane morphology were observed at only 5min after the plasma treatment. The primary role of reactive oxygen species (ROS) in this degradation is suggested. Deformation and condensation of the cell nucleus were observed 2–3 h after the treatment and are supposedly related to apoptosis induction. The coupling of the phase QWLSI with immunofluorescence imaging would give a deeper insight into the mechanisms of plasma induced cell death.

Added: Mar 7, 2016
Article
Fedorov G., Kardakova A., Gayduchenko I. et al. Applied Physics Letters. 2013. Vol. 103. P. 181121-1-181121-5.

We report on the voltage response of carbon nanotube devices to sub-terahertz (THz) radiation. The devices contain carbon nanotubes (CNTs), which are over their length partially suspended and partially Van der Waals bonded to a SiO2 substrate, causing a difference in thermal contact. We observe a DC voltage upon exposure to 140GHz radiation. Based on the observed gate voltage and power dependence, at different temperatures, we argue that the observed signal is both thermal and photovoltaic. The room temperature responsivity in the microwave to THz range exceeds that of CNT based devices reported before.

Added: Mar 13, 2014
Article
P. Melentiev, A. Kalmykov, A. Gritchenko et al. Applied Physics Letters. 2017. Vol. 111. P. 213104.

We demonstrate intracavity plasmonic laser spectroscopy using a plasmonic laser created from a periodically perforated silver film with a liquid gain medium. An active zone of the laser is formed by a highly elongated spot of pumping. This results in a significantly more efficient diffusive mixing of dye molecules, which suppresses the effect of their bleaching, and in the ability to reduce the volume of the gain medium to as little as 400 nl. We use this design for a stable plasmonic laser in multiple measurements and demonstrate that it is highly effective as a spaser spectroscopy sensor for intracavity detection of an absorptive dye at 0.07 ppm. This work provides an opportunity to develop applications of intracavity plasmonic laser spectroscopy in biological label detection and other fields.

Added: Nov 27, 2019
Article
Нечепуренко И. А. Applied Physics Letters. 2017. Vol. 111. No. 21. P. 213104-1-213104-5.

We demonstrate intracavity plasmonic laser spectroscopy using a plasmonic laser created from a periodically perforated silver film with a liquid gain medium. An active zone of the laser is formed by a highly elongated spot of pumping. This results in a significantly more efficient diffusive mixing of dye molecules, which suppresses the effect of their bleaching, and in the ability to reduce the volume of the gain medium to as little as 400 nl. We use this design for a stable plasmonic laser in multiple measurements and demonstrate that it is highly effective as a spaser spectroscopy sensor for intracavity detection of an absorptive dye at 0.07 ppm. This work provides an opportunity to develop applications of intracavity plasmonic laser spectroscopy in biological label detection and other fields.

Added: Feb 7, 2019
Article
Балыкин В. И., Калмыков А. С., Gritchenko A. S. et al. Applied Physics Letters. 2017. Vol. 111. No. 21. P. 213104-1-213104-5.

We demonstrate intracavity plasmonic laser spectroscopy using a plasmonic laser created from a periodically perforated silver film with a liquid gain medium. An active zone of the laser is formed by a highly elongated spot of pumping. This results in a significantly more efficient diffusive mixing of dye molecules, which suppresses the effect of their bleaching, and in the ability to reduce the volume of the gain medium to as little as 400 nl. We use this design for a stable plasmonic laser in multiple measurements and demonstrate that it is highly effective as a spaser spectroscopy sensor for intracavity detection of an absorptive dye at 0.07 ppm. This work provides an opportunity to develop applications of intracavity plasmonic laser spectroscopy in biological label detection and other fields.

Added: Feb 4, 2019
Article
Bakurskiy S. V., Klenov N. V., Soloviev I. I. et al. Applied Physics Letters. 2018. Vol. 113. No. 082602. P. 082602-1-082602-5.

We study the peculiarities in current-phase relations (CPR) of the SIsFS junction in the region of 0 to p transition. These CPR consist of two independent branches corresponding to 0- and p-states of the contact. We have found that depending on the transparency of the SIs tunnel barrier, the decrease in the s-layer thickness leads to transformation of the CPR shape going in the two possible ways: either one of the branches exists only in discrete intervals of the phase difference u or both branches are sinusoidal but differ in the magnitude of their critical currents. We demonstrate that the difference can be as large as 10% under maintaining superconductivity in the s layer. An applicability of these phenomena for memory and logic application is discussed.

Added: Oct 28, 2018
Article
K.I. Kugel, Rozhansky I. V., Krainov I. V. et al. Applied Physics Letters. 2015. Vol. 106. No. 25. P. 252402-1-252402-5.
We apply the resonant indirect exchange interaction theory to explain the ferromagnetic properties of the hybrid heterostructure consisting of a InGaAs-based quantum well (QW) sandwiched between GaAs barriers with spatially separated Mn delta-layer. The experimentally obtained dependence of the Curie temperature on the QW depth exhibits a peak related to the region of resonant indirect exchange. We suggest the theoretical explanation and a fit to this dependence as a result of the two contributions to ferromagnetism—the intralayer contribution and the resonant exchange contribution provided by the QW.
Added: Mar 11, 2016
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