Volume 106, Nº 8 (2017)

Fe_xMn_1−xS belongs to the group of strong electron correlations compounds MnO. We present here experimental results for the antiferromagnetic iron–manganese sulfide system, based on X-ray and neutron diffraction studies. The neutron diffraction investigations were carried out at ambient conditions and at hydrostatic pressures up to 4.2 GPa in the temperature range from 65 to 300 K. Our results indicate that the Néel temperature of α-MnS increases up to room temperature by applying chemical (x_Fe) or weak hydrostatic pressure P. In Fe_0.27Mn_0.73S, the Néel temperature increases from 205(2) K (P = 0 GPa) to 280(2) K (P = 4.2 GPa) and the magnetization at 100 K decreases by a factor of 2.5 when the hydrostatic pressure increases from 0 to 4.2 GPa.

Recently, we have suggested Fermi-liquid–non-Fermi-liquid angular crossovers that may exist in quasi-one-dimensional (Q1D) conductors in high tilted magnetic fields (see A. G. Lebed, Phys. Rev. Lett. 115, 157001 (2015)). All calculations in the Letter were done by using the quasiclassical Peierls substitution method, whose applicability in high magnetic fields was questionable. Here, we solve a fully quantum mechanical problem and show that the main qualitative conclusions of the work cited above are correct. In particular, we show that in high magnetic fields, applied along one of the two main crystallographic axis, we have 2D electron spectrum, whereas, for directions of high magnetic fields far from the axes, we have 1D electron spectrum. The latter is known to promote non-Fermi-liquid properties. As a result, we expect the existence of Fermi-liquid–non-Fermi-liquid angular crossovers or phase transitions. Electronic parameters of Q1D conductor (Per)₂Pt(mnt)₂ show that such transitions can appear in feasible high magnetic fields of the order of H ≃ 20–25 T.

The patterns of propagation of gigahertz surface acoustic waves (SAWs) are obtained for cuts of CdZnTe single crystals with different crystallographic orientations. By comparing the experimental patterns with the calculated ones, the existence of at least two SAW modes, one of which is a Rayleigh mode, is demonstrated. It is shown that the anisotropy of propagation of different SAW modes makes it possible to determine the local crystallographic orientation of the CdZnTe surface and detect local imperfections of the crystal structure. Strong anisotropic scattering of the Rayleigh wave by coherent twin boundaries is found.

A polaron state of an electron in a hybrid system composed of a two-dimensional electron gas and a Bose–Einstein condensate of excitons situated in a quantum well coplanar with the electron gas has been investigated. It has been shown that self-localization is possible even at a weak coupling between the components of the structure, when a fluctuation of the density of excitons producing a potential well for the electron is small compared to their average density.

For the first time, nanoengineered polymeric capsules and their architecture have been studied with coherent X-ray diffraction imaging technique. The use of coherent X-ray diffraction imaging technique allowed us to analyze the samples immersed in a liquid. We report about the significant difference between polymeric capsule architectures under dry and liquid conditions.

It has been shown that a dusty plasma is formed in the surface layer over the illuminated part of Mars’ satellite Phobos owing to photoelectric and electrostatic processes. The distribution functions of photoelectrons near its surface, altitude dependences of the density of dust particles, and their charges and sizes, as well as electric fields, have been determined within a physicomathematical model for the self-consistent description of densities of photoelectrons and dust particles over the surface of the illuminated part of Phobos. In view of a weak gravitational field, dust particles rising over the surface of Phobos are larger than those over the surface of the Moon. In this case, the role of adhesion, which is a significant process preventing the separation of dust particles from the lunar surface, is much smaller on Phobos.

The possibility of laboratory X-ray reflectometry study of the structure of dimyristoyl phosphatidylserine (DMPS) phospholipid monolayers on the water surface in various phase states has been demonstrated.

It was shown in JETP Lett. 102, 508 (2015) that the intensity correlation function of the emission from a high-quality-factor semiconductor microcavity under resonant optical pumping exhibits an oscillatory behavior with an unexpectedly long oscillation period and a long decay time, which fall in the nanosecond range. A further investigation demonstrates that the origin of these oscillations is not related to the weak Rabi interaction between long-lived localized exciton states in the quantum well and the electromagnetic field of the microcavity mode. It proves that the semiconductor microcavity plays a secondary role in the observation of nonclassical light: it provides the spectral selection of the modes of the pump laser. We believe that intrinsic instabilities lead to the chaotic excitation of spiking in the laser modes under a constant operating current.