论文标题
典型的特定热量的特定热量的库层超导体yba $ _2 $ cu $ _4 $ o $ _8 $
Field-dependent specific heat of the canonical underdoped cuprate superconductor YBa$_2$Cu$_4$O$_8$
论文作者
论文摘要
与大多数其他丘比特相比，与大多数其他酸奶相比，Cuprate超导体YBA $ _2 $ _4 $ _4 $ _8 $具有稳定的石学计量，在很大程度上没有缺陷，并且可以被视为规范不足的铜层，表现出明显的Pseudogap行为，表现出明显的Pseudogap行为和相关的弱化性属性。该铜酸盐的“假单胞菌”表现为在费米水平的状态的电子密度中的部分间隙，并且在大多数光谱特性中都可以观察到。经过几十年的深入研究，人们普遍认为，伪群在特征温度（$ t^*$）上关闭，均值，$ t^*$，随着孔浓度的降低，$ t^*$上升，$ p $。在这里，我们报告了对YBA $ _2 $ _2 $ _4 $ _4 $ o $ $ _8 $的广泛依赖于现场的特定热量研究，直至前所未有的400 k，并明确地表明，伪gap永远不会关闭，至少可以在400 k中开放，至少要在$ t^*$上显示$ t^$。在数值上与近节状态的弱相互交互的费米安系统一致。并且，从依赖于场的比热中，我们表征了波动和杂质散射对热力学特性的影响。
The cuprate superconductor YBa$_2$Cu$_4$O$_8$, in comparison with most other cuprates, has a stable stoichiometry, is largely free of defects and may be regarded as the canonical underdoped cuprate, displaying marked pseudogap behaviour and an associated distinct weakening of superconducting properties. This cuprate `pseudogap' manifests as a partial gap in the electronic density of states at the Fermi level and is observed in most spectroscopic properties. After several decades of intensive study it is widely believed that the pseudogap closes, mean-field like, near a characteristic temperature, $T^*$, which rises with decreasing hole concentration, $p$. Here, we report extensive field-dependent electronic specific heat studies on YBa$_2$Cu$_4$O$_8$ up to an unprecedented 400 K and show unequivocally that the pseudogap never closes, remaining open to at least 400 K where $T^*$ is typically presumed to be about 150 K. We show from the NMR Knight shift and the electronic entropy that the Wilson ratio is numerically consistent with a weakly-interacting Fermion system for the near-nodal states. And, from the field-dependent specific heat, we characterise the impact of fluctuations and impurity scattering on the thermodynamic properties.
