Shi, Li-Bin; Wang, Yong Ping
The native defects and magnetic properties in undoped rutile TiO2 are studied using local density approximation (LDA) and LDA adding Hubbard parameters (U) schemes. The band gap is adjusted to experimental value of 3.0 eV by combination of UTi d=4.2 eV and UO p=4.8 eV. This LDA+U methodology overcomes the band-gap problem and renders the approach more predictive. The formation energies of oxygen vacancy (VO), oxygen interstitial (Oi), titanium vacancy (VTi), titanium interstitial (Tii), oxygen anti-sites (OTi), and titanium anti-sites (TiO) are investigated by the LDA and LDA+U methods. In addition, some ground state configurations can be obtained by optimization of total spin. It is found that native defects can induce spin polarization and produce magnetic moment.
V. I. Sakharov's (1911-1991) scientific contribution to the research of the problem of latitude variation and the Earth pole motion. (Russian Title: On nauchnom puti V. I. Sakharova (1911-1991) v issledovanii problemy izmenyaemosti shirot i dvizheniya polyusov Zemli)
Kostina, L. D.
V. I. Sakharov - the known Soviet astronomer and geodynamist, one of the leading specialists in the Soviet Union on the problem of latitude variation and the Earth pole motion, Doctor in physics and mathematics. He took part in the Great Patriotic War. For more than 40 years he worked at the Pulkovo observatory. He took an active part in the restoration of the latitude service of the completely destroyed observatory during the war. He was a skilful observer with zenith-telescopes, the ZTF-135 and the ZTL-180, and a fine investigator of them. He made original researches using the results of Pulkovo latitude observations with the zenith-telescope ZTF-135 and other data which made substantial contributions to the problem at hand. Some results of the investigations were achieved by V. I. Sakharov for the first time in the world. He was the author of the fundamental work on the analysis of the 19-year Pulkovo latitude series obtained with the zenith-telescope ZTF-135 (1948-1967). He investigated the regularity of the Earth pole motion. He was the first astronomer in the world who revealed the first 40-year period of the amplitude variation of the Chandler pole motion in the twentieth century and studied the peculiarities of the curve of the amplitude variation of the Chandler pole motion. He was the first to investigate the extreme cycles of the Earth pole motion. He stated that the character of the mechanism of the damping of the Chandler pole motion was practically constant. The results of the determination of the period of the Chandler pole motion by V. I. Sakharov testify to the accuracy of the one-component model. V. I. Sakharov determined the relaxation time of the Chandler pole motion. He was one of the initiators of the creation and working out of the technical task of the largest in the world zenith-telescope, the ZTL-180. He was one of the organisers of the parallel latitude observations with two zenith-telescopes at Pulkovo. He was a member of the International Astronomical Union since 1964.