Origin of the inner ring in photoluminescence patterns of quantum well excitons

In order to explain and model the inner ring in photoluminescence (PL) patterns of indirect excitons in GaAs/AlGaAs quantum wells (QWs), we develop a microscopic approach formulated in terms of coupled nonlinear equations for the diffusion, thermalization and optical decay of the particles. The origin of the inner ring is unambiguously identified: it is due to cooling of indirect excitons in their propagation from the excitation spot. We infer that in our high-quality structures the in-plane diffusion coefficient is about 10-30cm^2/s and the amplitude of the disorder potential is about 0.45meV.Comment: 4 pages, 3 figure

Theory of condensation of indirect excitons in a trap

We present theoretical studies of condensation of indirect excitons in a trap. Our model quantifies the effect of screening of the trap potential by indirect excitons on exciton condensation. The theoretical studies are applied to a system of indirect excitons in a GaAs/AlGaAs coupled quantum well structure in a diamond-shaped electrostatic trap where exciton condensation was studied in earlier experiments. The estimated condensation temperature of the indirect excitons in the trap reaches hundreds of milliKelvin

The Interaction in the Macroscopically Ordered Exciton State

The macroscopically ordered exciton state (MOES) - a periodic array of beads with spatial order on a macroscopic length - appears in the external exciton rings at low temperatures below a few Kelvin. Here, we report on the experimental study of the interaction in the MOES. The exciton PL energy varies in concert with the intensity along the circumference of the ring, with the largest energy found in the brightest regions. This shows that the MOES is characterized by the repulsive interaction and is not driven by the attractive interaction.Comment: 3 pages, 3 figure

Kinetics of Exciton Emission Patterns and Carrier Transport

We report on the measurements of the kinetics of expanding and collapsing rings in the exciton emission pattern. The rings are found to preserve their integrity during expansion and collapse, indicating that the observed kinetics is controlled by charge carrier transport rather than by a much faster process of exciton production and decay. The relation between ring kinetics and carrier transport, revealed by our experiment and confirmed by comparison with a theoretical model, is used to determine electron and hole transport characteristics in a contactless fashion.Comment: 6 pages, 4 figure

Pattern Formation as a Signature of Quantum Degeneracy in a Cold Exciton System

The development of a Turing instability to a spatially modulated state in a photoexcited electron-hole system is proposed as a novel signature of exciton Bose statistics. We show that such an instability, which is driven by kinetics of exciton formation, can result from stimulated processes that build up near quantum degeneracy. In the spatially uniform 2d electron-hole system, the instability leads to a triangular lattice pattern while, at an electron-hole interface, a periodic 1d pattern develops. We analyze the mechanism of wavelength selection, and show that the transition is abrupt (type I) for the uniform 2d system, and continuous (type II) for the electron-hole interface.Comment: 5 pages, 3 figure

Стратегия развития автомобилестроительной компании на российском авторынке на примере ПАО «Соллерс»

The article analyses the dynamics of development of the Russian market of passenger cars and light commercial vehicles, investigates the strategy and competitive advantages of Sollers group of companies, which is successfully operating despite volatility of development of the Russian car market, as well as the need for a radical renewal of the model range of the company’s cars, the presence of excess production capacity and the departure from Russia of three foreign partners of Sollers group of companies in joint ventures: Fiat, SsangYong and Ford. Particular attention in the article is paid to Ford, a joint venture partner with Sollers PJSC, which left the Russian domestic market in 2019. This event, which had a negative impact on partners and clients of the company, was caused by severalcircumstances. Besides, the article identifies the main directions of development of joint ventures Mazda Sollers and Ford Sollers (in terms of Ford Transit minibus, the only locally manufactured Ford model) and the possibility of expanding their export potential, including due to export of engines, spare parts and components.The article pays close attention to introduction of new technologies in Sollers PJSC and other companies, development of digitalisation in development and production of new models, creation of its own telematics platform that allows to connect a car to the Internet and control it remotely, including starting the engine.The author examines in detail a new consumption model in the car market associated with refusal of buyers to own a car and with emerging choice of new services regarding subscription and exchange of cars, their development in foreign and domestic markets, as well as offers the analysis of successes and failures of foreign automakers in providing subscription services.The main purpose of the article is to study the strategy of Sollers PJSC in the domestic and foreign markets, auxiliary purposes refer to the analysis of the domestic market, change in the consumption model and provision of new services, study of reasons for departure of foreign partners of the company.В представленной статье проведён анализ динамики развития российского рынка легковых и лёгких коммерческих автомобилей, исследованы стратегия и конкурентные преимущества группы компаний «Соллерс», которая успешно функционирует, несмотря на волатильность развития российского авторынка, необходимость кардинального обновления модельного ряда автомобилей компании, наличие избыточных производственных мощностей и уход из России трёх зарубежных партнёров ГК «Соллерс» по совместным предприятиям – компаний Fiat, SsangYong и Ford. Особое внимание в статье уделено партнёру по совместному предприятию с ПАО «Соллерс» компании Ford, которая покинула отечественный рынок в 2019 году. Это событие, негативно отразившееся на партнёрах и клиентах компании, было обусловлено целым рядом обстоятельств. Кроме того, в статье выявлены основные направления развития совместных предприятий Mazda Sollers и Ford Sollers (в части единственной оставшейся в российском производстве модели Ford – микроавтобуса Ford Transit) и возможности расширения их экспортного потенциала, в том числе за счёт экспорта двигателей, запасных частей и комплектующих.Пристальное внимание в статье уделено внедрению новых технологий в ПАО «Соллерс», развитию цифровизации в разработке и производстве новых моделей, созданию собственной телематической платформы, позволяющей подключить автомобиль к интернету и управлять им дистанционно, включая запуск двигателя.Автором подробно рассмотрена новая модель потребления на авторынке, связанная с отказом покупателей от владения автомобилем и выбором новых услуг по подписке и обмену автомобилей, их развитием на зарубежном и отечественном рынках, а также проведён анализ успехов и неудач зарубежных автопроизводителей по предоставлению услуг по подписке.Главной целью статьи является исследование стратегии ПАО «Соллерс» на отечественном и зарубежных рынках, вспомогательными целями – анализ отечественного рынка, изменения модели потребления и предоставления новых услуг, изучение причин ухода зарубежных партнёров компании