---

Condensed Matter Theory Group

Current Research Focus
Group Staff
Recent Publications
Books and Reviews
Research Retrospective
Contact Information

Welcome to the website of Condensed Matter Theory Group founded by Professor Iya Ipatova (1929-2003) at Ioffe Institute of Russian Academy of Sciences. Our group's interests focus on understanding the physical processes in semiconductor technology. Our goal is to develop theoretical concepts and computational methods that enable us to optimise the semiconductor growth technology processes.

Another subjects of our interest are the optical properties of semiconductor nanostructures with the special interest in polaron effects in the wide bandgap nanostructures.

• Decomposition of semiconductor alloy epitaxial films: spinodal decomposition, kinetic decomposition
  Spontaneous formation of nanometer-scale composition modulated structures is a common phenomenon for the A^IIIB^V and A^IIB^VI semiconductor alloys (of cubic or hexagonal symmetry). It is shown that the characteristic elastic energy of an alloy governs the process of decomposition. Fluctuations of composition in the growing epitaxial semiconductor film are in charge of the stability of the growing alloy. We study two possible instabilities of the alloy: the equilibrium spinodal decomposition and the nonequilibrium kinetic instability. The effect of the surface relaxation on the critical temperature of spinodal decomposition is taken into account. Nonlinear kinetic theory of alloy phase separation in open system is considered.
• Theory of spontaneous formation of quantum dot arrays
  Theories for the spontaneous formation of arrays of strained islands in heteroepitaxial semiconductor systems are developed. It is shown that an array of three-dimensional coherent strained islands in a heteroepitaxial system is stable against Ostwald ripening; such equilibrium array can serve as an array of quantum dots. It is established that the elastic anisotropy of a semiconductor governs the structure of multi-layered arrays of strained islands: namely, islands in neighboring layers undergo transitions between in-phase and out-of-phase vertical correlation, such a transition being driven by the spacer thickness. Entropy-driven decrease of an average island volume with the formation temperature allows distinguishing of thermodynamic-controlled arrays of islands from kinetic-controlled ones.
• Large radius polarons in semiconductor nanostructures: polaron exciton
  Recent experimental data have shown that the line of exciton transition in quantum dot is accompanied by multiple phonon replicas indicating the strong polarization of the medium by the exciton. We study the polarization effects of the exciton and calculate polaron energies of electron and the hole; it has been shown that phonon replica spectral lines are well resoled in quantum dot. Effects of Yahn-Teller interaction and surface phonons are considered.

1. А.Ю. Маслов, О.В. Прошина. Роль интерфейсных фононов при формировании поляронных состояний в квантовых ямах. ФТП 44 (2), 200-204 (2010)
2. A.Yu. Maslov, O.V. Proshina. Interface phonons and polaron effect in quantum wires. Nanoscale Res. Lett., DOI 10.1007/s11671-010-9704-0, 1-5 (2010)
3. A.Yu. Maslov, O.V. Proshina. Interface phonons and dielectric enhancement effects on excitons in quantum well. Superlattices Microstruct. 47 (1), 213-215 (2010)
4. A.Yu. Maslov, O.V. Proshina. Interface phonons and polaron effect in II-VI quantum well. Phys. Status Solidi C 7 (6), 1609-1611 (2010)
5. A.Yu. Maslov, O.V. Proshina. New method for control over exciton states in quantum wells. J. Phys.: Conf. Ser. 210 (1), 012055 (2010)
6. М.Е. Компан, В.П. Кузнецов, В.Г. Малышкин. Нелинейный импеданс твердотельных энергонакопительных конденсаторов-ионисторов. ЖТФ 80 (5), 100-106, (2010)
7. M.B. Lifshits, M.I. Dyakonov. Swapping Spin Currents: Interchanging Spin and Flow Directions Phys. Rev. Lett. 103, 186601 (2009)
8. I.V. Rozhansky, M.B. Lifshits, S.A. Tarasenko, N.S. Averkiev. Conversion of hole states by acoustic solitons. Phys. Rev. B, 80, 085314 (2009)
9. M.B. Lifshits, M.I. Dyakonov. Photovoltaic effect in a gated two-dimensional electron gas in magnetic field. Phys. Rev. B, 80, 121304(R) (2009)
10. И.Ю. Сапурина, М.Е. Компан, В.Г. Малышкин, В.В. Розанов, Я. Стейскал. Свойства протонпроводящих мембран типа "Нафион" с поверхностными наноразмерными слоями электропроводящего полианилина. Электрохимия 45 (6), 744-754 (2009)
11. A.Yu. Maslov, O.V. Proshina, A.N. Rusina. Interface phonon effect on optical spectra of quantum nanostructures. J. Lumines 129 (12), 1934-1936 (2009)
12. А.Ю. Маслов, О.В. Прошина. Влияние спектра элементарных возбуждений на спинодальный распад полупроводниковых твердых растворов. ФТП 43 (7), 873-877 (2009)

1. V.A. Shchukin, N.N. Ledentsov, D. Bimberg. Epitaxy of nanostructures. Springer-Verlag, 2003, pp 392
2. И.П. Ипатова, В.Ф. Мастеров, Ю.И. Уханов. Курс физики. Том 2. Санкт-Петербург, издательство СПбГТУ,  322 стр., 2003 (in Russian)
   [I.P. Ipatova, V.F. Masterov, Yu.N. Ukhanov. Physics v.II: Electromagnetism. Technical University Press Center, St.Petersburg, Russia, 2003]
3. И.П. Ипатова, В.Ф. Мастеров, Ю.И. Уханов. Курс физики. Том 1. Механика. Термодинамика. Санкт-Петербург, издательство СПбГТУ,  388 стр., 2001 (in Russian)
   [I.P. Ipatova, V.F. Masterov, Yu.N. Ukhanov. Physics v.I: Mechanics and Thermodynamics. Technical University Press Center, St.Petersburg, Russia, 2001]
4. I.P. Ipatova. Quantum Solid State Theory. Elementary Exitations. Technical University Press Center, St.Petersburg, Russia, 1999 (in Russian)
5. I.P. Ipatova. Quantum Solid State Theory. Band Structure. Technical University Press Center, St.Petersburg, Russia, 1998 (in Russian)
6. I. Ipatova, V. Mitin. Introduction to Solid State Electronics. Addison-Wesley Publishing Company, 1996, pp 354
7. V.N. Vinchakov, I.P. Ipatova. Applications of Tensors and Matrices in Solid State Physics. Technical University Press Center, St.Petersburg, Russia, 1979, pp 75 (in Russian)

8. A.A. Marardudin, E. Montroll, J. Weiss, I.P. Ipatova. Lattice Dynamics in Harmonic Approximation. Academic Press, New York, 1971, pp 543

1. V.A. Shchukin and D. Bimberg. Spontaneous ordering of nanostructures on crystal surfaces. Rev. Mod. Phys. Vol. 71, No.4, pp. 1125-1171, 1999
2. N.N. Ledentsov, V.M. Ustinov, V.A. Shchukin, P.S. Kop'ev, Zh.I. Alferov, and D. Bimberg. Quantum dot heterostructures: fabrication, properties, lasers (Review). Fiz. Tekh. Poluprovodn. vol. 32, No. 4, pp. 385-410, 1998 [Semiconductors, vol. 32, No. 4, pp. 343-365, 1998]
3. V.A. Shchukin and D. Bimberg. Strain-driven self-organization of nanostructures on semiconductor surfaces. Appl. Phys. A vol. 67, pp. 687-700, 1998
4. I.P. Ipatova, A.A. Maradudin. Lattice Vibrations, Statistics of. Enciclopedia of Applied Physics, l.8, pp. 465-484, 1994
5. B.H. Bairamov, I.P. Ipatova, V.A. Voitenko. Light Scattering from Current Carriers in Semiconductors. Phys. Reports v.229, No 5, pp. 223-290, 1993
6. B.H. Bairamov, I.P. Ipatova, V.A. Voitenko, Light Scattering from Electron Density Fluctuations in Manyvalley Semiconductors, Sov. Phys. Uspekhi v.36, No 5, pp. 392-435, 1993
7. M. Cardona, I. Ipatova. Effect of Electron Excitations on Light Scattering and Phonons. in: Elementary Excitations in Solids, ds, J.L. Birman, C. Sebenne, R.F. Wallis, North Holland, Amsterdam, pp. 237-282, 1992 download PDF
8. I.P. Ipatova. Universal Parameters in Mixed Crystals. In: Modern Problems of Condensed Matter, vol. 23, "Optical Properties of Mixed Crystals", eds, R.J. Elliott and I.P. Ipatova, North Holland Publishing House, Amsterdam, pp. 1-14, 1988
9. I.P. Ipatova, Yu.E. Kitaev. Landau Theory of Second Order Phase Transitions on the Solid State Surfaces. Progress in Surface Science, vol. 18, No. 3, pp. 189-246, 1985