Quantum effects in silicon isotopes at low temperatures under normal and high pressures

Abstract

Precision studies of Raman scattering in isotopically pure28Si,29 Si, and30 Si single crystals have been performed in the temperature range from 8 to 300 K. It was found that the quantum effects manifest themselves noticeably at low temperatures (T≤100 K). This can be seen from the difference ∼(0.4±0.1) cm−1between the normalized frequencies of two extreme28Si and30 Si isotopes, while at room temperature, quantum effects are not visible and are comparable with the measurement error of frequencies (0.1 cm−1 ). Raman scattering in silicon isotopes in the region of noticeable quantum effects has been studied under hydrostatic conditions at pressures to 12 GPa and at a temperature of Т=80 K. Quantum effects are not changed under compression within the accuracy of measurements.