发表机构
University of Oxford（牛津大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究结合路径积分与晶格动力学方法，明确核量子效应等因素对固态仲氢热导率的关键作用，揭示低温下热输运由集体弛豫子模式主导，为量子晶体热输运研究提供了重要依据。
AI 中文摘要
我们结合路径积分与晶格动力学方法计算固态仲氢的热导率。首先，采用路径积分分子动力学计算各温度下的质心平均力势，在此基础上通过有限位移法构建简谐声子基；随后计算质心势上的非简谐力常数，并求解线性化声子玻尔兹曼输运方程以得到热导率。所得的重正化声子色散曲线、热容及热导率均与实验测量值吻合极佳。研究发现，低温下热输运由集体弛豫子模式主导，无法通过声子弛豫时间近似描述；仅当明确考虑质心平均力势中的核量子效应、声子边界散射及流体动力学输运时，才能与实验热导率实现定量吻合，这一情况也可能适用于其他量子晶体。
英文摘要
We use a combination of path integral and lattice dynamics methods to calculate the thermal conductivity of solid parahydrogen. Path integral molecular dynamics is first used to calculate a centroid potential of mean force at each temperature, on which a harmonic phonon basis is constructed using the finite displacement method. We then calculate anharmonic force constants on the centroid potential and solve the linearised phonon Boltzmann transport equation for the thermal conductivity. The resulting renormalised phonon dispersion curves, heat capacity, and thermal conductivity are all in remarkably good agreement with experimental measurements. We find that the heat transport is dominated by collective relaxon modes at low temperatures and cannot be captured by making the phonon relaxation time approximation. Indeed, quantitative agreement with the experimental thermal conductivity is only achieved when the nuclear quantum effects in the centroid potential of mean force, phonon boundary scattering, and hydrodynamic transport are all explicitly considered. This is also likely to be the case for other quantum crystals.
Comments11 pages, 5 figures
