Investigation of electron correlation effect on energy spectrum of two-electron systems in crystals with strong electron-phonon coupling

• Дата: 2002
• Автори: Kashirina, N.I., Lakhno, V.D., Sychyov, V.V.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2002
• Назва видання: Semiconductor Physics Quantum Electronics & Optoelectronics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/121239
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Investigation of electron correlation effect on energy spectrum of two-electron systems in crystals with strong electron-phonon coupling / N.I. Kashirina, V.D. Lakhno, V.V. Sychyov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2002. — Т. 5, № 3. — С. 235-242. — Бібліогр.: 21 назв. — англ.

The influence of electron correlations (direct dependence of electronic wave function on distance between electrons) on energy spectra of two-electron systems (D-, F ', F₂-centers and bipolarons) in polar crystals with strong electron-phonon interaction is investigated. Bipolaron is chosen as the simplest model of two-electron system in the crystal. Bipolaron energy is calculated for various distances between the centers of polarization wells of two polarons with accounting the electron correlations. A singlet bipolaron is stable at rather high energy of ion binding η ≤ ηm ≈ 0,143 (η= ε∞/ η₀). The unique energy minimum corresponds to a one-center bipolaron (an analog of a helium atom). The bipolaron binding energy constitutes up to 25.8% of a double polaron energy at η → 0. A triplet bipolaron (an analog of orthohelium) is energetically disadvantageous. The one-center configuration of a triplet bipolaron corresponds to a maximum on the distance dependence of the total energy JBp(R). The exchange interaction between polarons has antiferromagnetic character. A prediction is made about a possibility of the Wigner crystallization of a polaron gas, which occurs with antiferromagnetic ordering in the polaron system. The examples of energy calculations with accounting the electron correlations of exchanged-coupled pairs, D- and F '-centers in polar crystals are also given.