arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0709.3075cond-mat.supr-concond-mat.str-el
收藏

铜酸盐单晶的低温声子热导率

Low-temperature phonon thermal conductivity of cuprate single crystals

S. Y. Li, J. -B. Bonnemaison, A. Payeur, P. Fournier, C. H. Wang, X. H. Chen, Louis Taillefer

摘要:

研究了样品尺寸和表面粗糙度对Nd $_2$ CuO $_4$单晶的声子热导率$κ_p$的影响,其热导率最低可达50 mK。在0.5 K下,$κ_p$与$\sqrt{A}$成比例,其中$A$是样品的横截面积。这表明,$κ_p$是占主导地位的边界散射低于0.5 K左右。然而,在低至50 mK时未观察到$κ_p$的预期$T^3$依赖性。在粗糙化的表面,恢复的$T^3$的依赖性,显示偏离$T^3$是由于声子的镜面反射离开镜样样品表面。我们提出了一个经验幂律拟合,$κ_p \sim T^α$(其中$α< 3$)在铜酸盐单晶。使用这种方法,我们表明,最近的热导率研究的Zn掺杂在YBa $_2$铜$_3$ O $_y$重申普遍的d波准粒子在$T \to 0$的热导率。

英文摘要:

The effect of sample size and surface roughness on the phonon thermal conductivity $κ_p$ of Nd$_2$CuO$_4$ single crystals was studied down to 50 mK. At 0.5 K, $κ_p$ is proportional to $\sqrt{A}$, where $A$ is the cross-sectional area of the sample. This demonstrates that $κ_p$ is dominated by boundary scattering below 0.5 K or so. However, the expected $T^3$ dependence of $κ_p$ is not observed down to 50 mK. Upon roughing the surfaces, the $T^3$ dependence is restored, showing that departures from $T^3$ are due to specular reflection of phonons off the mirror-like sample surfaces. We propose an empirical power law fit, to $κ_p \sim T^α$ (where $α< 3$) in cuprate single crystals. Using this method, we show that recent thermal conductivity studies of Zn doping in YBa$_2$Cu$_3$O$_y$ re-affirm the universal heat conductivity of d-wave quasiparticles at $T \to 0$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑