The influence of the addition of Bi to the (Ga,Mn)As dilute ferromagnetic semiconductor on its electronic structure as well as on its magnetic and structural properties has been studied. Epitaxial (Ga,Mn)(Bi,As) layers of high structural perfection have been grown using low-temperature molecular-beam epitaxy. Post-growth annealing of the samples improves their structural and magnetic properties and increases the hole concentration in the layers. Hard X-ray angle-resolved photoemission spectroscopy (HARPES) reveals a strongly dispersing band in the Mn-doped layers, which crosses the Fermi energy and is caused by the high concentration of Mn-induced itinerant holes located in the valence band. An increased density of states near the Fermi level is attributed to additional localized Mn states. In addition to a decrease of the chemical potential with increasing Mn doping, we find significant changes in the valence band caused by the incorporation of a small atomic fraction of Bi atoms. The spin-orbit split off band is shifted to higher binding energies, which is inconsistent with the impurity band model of the band structure in (Ga,Mn)As. Spectroscopic ellipsometry and modulation photoreflectance spectroscopy results confirm the valence band modifications in the investigated layers.

In the article, it is feasible to analyze the impact of the coronavirus on the financial sector of Ukraine as of 2021. The pandemic has become a real test both for the financial market of Ukraine and for the entire economic situation of our country. In particular, the first part analyzed the impact of the pandemic on the main macroeconomic indicators of the market. We determined that during the period from sowing to May last year, Ukraine's GDP decreased by five points, which negatively affected macroeconomic indicators and the general well-being of our population. The next one analyzed the macroeconomic indicators characterizing the state of the Ukrainian market, experienced the greatest float of COVID-19. We have determined that wages have undergone a sharp cut, which has decreased by 10% over several months. The next was the analysis of the inflation index, which increased during the quarantine period in March, but since April 2020 it has begun to file, due to the end of strict quarantine restrictions. The impact of the coronavirus on the exchange rate was also studied, which in April 2020 the dollar exchange rate began to fall, but since June we have seen its rapid growth. Next, we analyzed the NBU's foreign exchange interventions, it can be seen that in July 2020 the NBU began selling foreign currency to support the national hryvnia exchange rate. In general, during the quarantine period, the NBU sold $ 1,160,000,000 in order to support the hryvnia. Enterprises in connection with punishing them with restrictions were forced to issue stocks and bonds in order to stay afloat. As a result, we can safely say that the coronavirus epidemic had a negative impact on the financial market of Ukraine and left a "black spot" on the economy of our state. It can be concluded that the situation with the pandemic does not bode well not only for the Ukrainian market, but also for the economy as a whole, and if this virus continues to develop, the hryvnia exchange rate may collapse. To date, the consequences of the infection have caused a serious disruption in the Ukrainian economy. In this situation, one can only hope that Ukrainian exports will grow in positive dynamics, which will allow our state to receive stable financial flows in foreign currency and in accordance with strengthening its own rate.

The article aims at analyzing the Ukrainian market of domestic government bonds (IGLBs) in the context of the COVID-19 pandemic; determining its state, problems and development perspectives. The development of the domestic government bonds market during the coronavirus crisis is considered; the essence and purpose of IGLBs in Ukraine are revealed; IGLBs are classified by type of use. The differences between domestic and external government bonds are determined, and the advantages of the former are indicated; peculiarities of purchasing such securities by individuals and legal entities are revealed; requirements for issuing IGLBs by issuers are indicated, and the most reliable banks engaged in this activity are enumerated; the state of the government bond market during 2018–2020 is studied; the amount of ownership, the share of buyers of securities and the purpose of their purchase for each of the entities are given; the rate and yield of domestic government bonds in Ukraine are analyzed and compared with other countries, such as the United States, Germany, France and others. The study identifies the following problems: the economic crisis caused by the COVID-19 pandemic, the inadequate legal framework on IGLBs, the low level of public awareness of these securities, and others. To overcome these problems, the following actions are suggested: counteracting the coronavirus crisis by combining the efforts of the state and local authorities, business, and the population; directing most of the financial resources in this direction; spreading economic education among the population; introducing a simplified procedure for purchasing IGLBs; and working with banks to increase the availability of bonds purchasing. Statistical data obtained from the official website of the National Bank of Ukraine make up the basis for the study.

No abstract