Theory of Symmetry

The theories of antisymmetry, similarity symmetry, and color symmetry groups were developed.

Structure

The atomic structures of several hundreds of materials were determined by modern X-ray, electron, and neutron diffraction methods from numerous minerals to the structures of biologically active crystals and macromolecules, and, first of all, of proteins. The imaging theory and the method of three-dimensional reconstruction from electron microscopy data were developed. The independent method of electron diffraction structure analysis was developed. The methods for studying structures of surfaces, thin films, and multilayer systems were developed including the structure-sensitive method of X-ray standing waves. First Russian diffractometers, X-ray cameras, multicrystal spectrometers, and other instruments were designed and manufactured. All the prerequisites for high-resolution diffraction experiments were created, including the design of special complexes of apparatus or «stations» for studying structures and properties of various materials on the synchrotron-radiation sources and the development of all the necessary methods.

Properties

The relationships between the structures and the physical properties have been established for various ferroelectrics, optically active and liquid crystals, superionics, high-temperature superconductors and also scintillating, magnetic, nonlinear optical, acoustooptical, and other crystalline materials. New crystalline media with specific physical properties were discovered, including numerous lasing crystals, media for liquid-crystal displays, holographic media, etc. The Institute was the first to discover the phenomena of electrogyration and the photovoltaic effect, to develop the Fourier spectroscopy, and to establish the domain structure of ferroelectrics and ferroelectric properties of two-dimensional systems.

Growth

The theory of crystallization was developed including the fundamentals of elementary growth processes. A helical relief of the surface of a growing crystal was established. The method of artificial epitaxy of thin films was developed as well as the controlled growth of tip crystals and solid-phase intergrowth of single crystals. For the first time, single-crystal germanium and silicon layers were obtained, and a special method was suggested for growth of bicrystals. The first experiments on crystal growth under the microgravity conditions were performed onboard the Salyut-5 orbital stations. The method of horizontal crystallization of refractory materials was developed. Special technologies and apparatus were designed for growth of various specific crystals, including the crystals used as active elements of tunable lasers. The technologies for growing quartz, Rochelle salt, various piezoelectrics, ruby, and optically nonlinear crystals were developed and scaled-up for their industrial production.