| Records |
| Author |
Varyukhin, S. V.; Zakharov, A. A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M. |
| Title |
Low energy excitation in La2CuO4 |
Type |
Journal Article |
| Year |
1990 |
Publication |
Sverkhprovodimost': Fizika, Khimiya, Tekhnika |
Abbreviated Journal |
Sverkhprovodimost': Fizika, Khimiya, Tekhnika |
| Volume |
3 |
Issue |
5 |
Pages |
832-837 |
| Keywords |
metal-dielectric-La2CuO4, monocrystals |
| Abstract |
Measurements of transmission and photoconductivity spectra in submillimeter wave length range as well as of capacity C and conductivity G in the region of acoustic frequencies of metal-dielectric-La2CuO4 system at low temperatures are performed using La2CuO4 monocrystals. Optical spectra posses a threshold character, a sharp decrease of transmission and photocoductivity signal occurs in the energy region hν>1.5 MeV. C(ω,T) and G(ω, T) dependences have a universal form typical of Debye type relaxation processes. Relaxation time dependence is of thermoactivated character τ(T)∼exp(ξ/T) with the gap value ξ≅2 meV. It is assumed that excitations with characteristic energy of ∼2 meV exist in La2CuO4. A possible nature of the detected low-energy excitations is discussed. |
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1688 |
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Voevodin, E. I.; Gershenzon, E. M.; Goltsman, G. N.; Ptitsina, N. G. |
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Energy-spectrum of shallow acceptors in Ge deformed strongly by a uniaxial pressure |
Type |
Journal Article |
| Year |
1989 |
Publication |
Sov. Phys. and Technics of Semiconductors |
Abbreviated Journal |
Sov. Phys. and Technics of Semiconductors |
| Volume |
23 |
Issue |
8 |
Pages |
843-846 |
| Keywords |
Ge, crystallography |
| Abstract |
Проведены исследования спектров фототермической ионизации мелких акцепторов (В, Аl) в Ge, предельно сжатом вдоль кристаллографической оси [100]. Из данных измерений с учетом теории построен энергетический спектр примесей. Показано, что энергии большого числа уровней четных и нечетных состояний хорошо соответствуют расчету, выполненному для примесей в анизотропном полупроводнике с параметром анизотропии γ=m∗⊥/m∗∥>1. |
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Энергетический спектр мелких акцепторов в сильно одноосно деформированном Ge |
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1692 |
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Voevodin, E. I.; Gershenzon, E. M.; Goltsman, G. N.; Ptitsina, N. G.; Chulkova, G. M. |
| Title |
Capture of free holes by charged acceptors in uniaxially deformed Ge |
Type |
Journal Article |
| Year |
1988 |
Publication |
Fizika i Tekhnika Poluprovodnikov |
Abbreviated Journal |
Fizika i Tekhnika Poluprovodnikov |
| Volume |
22 |
Issue |
3 |
Pages |
540-543 |
| Keywords |
Ge, free holes, capture |
| Abstract |
Цель настоящей работы — исследование кинетики примесной фотопроводимости p-Ge при сильном одноосном сжатии в широком диапазоне изменения интенсивности примесного подсвета, создающего свободные дырки, и определение сечения каскадного захвата дырок на мелкие заряженные акцепторы в условиях преобладания электрон-фононного механизма потерь энергии. |
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Russian |
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Захват свободных дырок заряженными акцепторами в одноосно деформированном Ge |
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1698 |
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Gershenzon, Ye. M.; Goltsman, G. N.; Yelantyev, A. I.; Petrova, Ye. B.; Ptitsina, N. G.; Filatov, V. S. |
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Lecture demonstrations of properties of superconductors and liquid helium |
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Journal Article |
| Year |
1987 |
Publication |
USSR Rept Phys. Math. JPRS UPM |
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USSR Rept Phys. Math. JPRS UPM |
| Volume |
24 |
Issue |
7 |
Pages |
51 |
| Keywords |
demonstrations, lections |
| Abstract |
New demonstrations for low temperature physics courses are described. Two transparent Dewar vacuum flasks fitting one inside the other with the external flask for nitrogen and the internal flask for helium are used. The helium temperature can be regulated in the 4.2 to 1.6 K range and the effects of reducing helium to the superfluid state at 2.17 K can be shown: boiling abruptly stops and superfluid flow appears. In order to show the electric and magnetic characteristics of superconductivity, a superconducting NbTi solenoid containing nonsuperconducting wire and germanium and superconducting Nb materials with different critical temperatures is placed in the helium refrigerant vessel. The fall of the resistance at the critical temperatures can be shown. In order to show magnetic field and superconductive current flow properties a shunt of superconductive material is connected in parallel to the coil and is enclosed in a teflon container with a heater which can vary its temperature. When it is heated and not superconductive, magnetic field effects can be demonstrated and when it is unheated and superconducting a continuous current can be demonstrated. |
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1704 |
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Gol'tsman, G. N.; Gusinskii, E. N.; Malyavkin, A. V.; Ptitsina, N. G.; Selevko, A. G.; Edel'shtein, V. M. |
| Title |
The excitonic Zeeman effect in uniaxially-strained germanium |
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Journal Article |
| Year |
1987 |
Publication |
Sov. Phys. JETP |
Abbreviated Journal |
Sov. Phys. JETP |
| Volume |
65 |
Issue |
6 |
Pages |
1233-1241 |
| Keywords |
Ge, Zeeman effect |
| Abstract |
We have carried out a high-resolution spectroscopic study of the absorption of submillimeter radiation by free excitons in germanium compressed along the [ 1 11 ] axis in a magnetic field parallel to the compression axis. In particular, we studied the splitting of the 1s- 2p transition in fields up to 6 kOe at T = 1.6 K, and observed a complex pattern in the Zeeman splitting which we believe is related to the effect of thermal motion of the excitons in a magnetic field on their internal structure (the magneto-Stark effect). The calculated submillimeter spectrum of excitons agrees with the experimental data. We predict that in a magnetic field the energy of the 2p, term is a minimum at a finite value of the exciton momentum perpendicular to the field-that is, the energy minimum forms a ring in momentum space. It follows that the density of states for this term must be a nonmonotonic function of the energy. A theory is developed of analogous phenomena in positronium. |
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1705 |
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