Vacancy Waves in a Quantum Solid ィイD13ィエD1He

点击翻译按钮获取中文摘要

We aim at verifying that the vacancies move as vacancy waves because of tunneling of ィイD13ィエD1He atoms in solid ィイD13ィエD1He. We studied the vacancy waves in three categories. (1) specific heat, (2) motion of dislocation and (3) zero point vacancy wave. (1) A spin polaron is a region where ィイD13ィエD1He spins are aligned ferromagnetically around a vacancy. We have observed an excess specific heat over the specific heat due to the exchange interaction. We checked whether it arises from spin polarons due to vacancies by applying a strong magnetic field. The results show that the excess specific heat does not arise from spin polarons but the amorphous solid ィイD13ィエD1He layers on the substrate. (2) We studied the motion of dislocations in solid ィイD13ィエD1He by the torsional oscillator technique. We studied the temperature dependence of the critical strain amplitude where the dissipation starts to increase.We have obtained clear evidence of the crossover from thermal to quantum tunneling of the dislocations through the Peierls potential. (3) We have been performing the experiment of pulsed NMR for depressurized solid in the fields of 8-15T. We aim at observing a decrease in TィイD21ィエD2 and increases in TィイD22ィエD2 and the diffusion constant due to the appearance of zero-point vacancy waves. So far, we have not yet confirmed the presence of zero-point vacancy waves.