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arXiv 2008.13692cond-mat.supr-con
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铜氧化物超导体Bi $_2$ Sr $_{2-x}$ La $_x$ CuO $_{6+δ}$赝能隙临界点的输运特征

Transport signatures of the pseudogap critical point in the cuprate superconductor Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+δ}$

M. Lizaire, A. Legros, A. Gourgout, S. Benhabib, S. Badoux, F. Laliberté, M. -E. Boulanger, A. Ataei, G. Grissonnanche, D. LeBoeuf, S. Licciardello, S. Wiedmann… 展开作者

M. Lizaire, A. Legros, A. Gourgout, S. Benhabib, S. Badoux, F. Laliberté, M. -E. Boulanger, A. Ataei, G. Grissonnanche, D. LeBoeuf, S. Licciardello, S. Wiedmann, S. Ono, H. Raffy, S. Kawasaki, G. -Q. Zheng, N. Doiron-Leyraud, C. Proust, L. Taillefer

摘要:

在正常状态下测量了五个铜酸盐超导体Bi $_2$ Sr $_{2-x}$ La $_x$ CuO $_{6+δ}$的输运系数,通过施加足够大的磁场(高达66 T)来抑制超导性。测量了两种过掺杂单晶的电阻率、霍耳系数、热导率、塞贝克系数和霍耳热导率,La浓度分别为$x = 0.2$($T_{\rm c}=18$ K)和$x = 0.0$($T_{\rm c}=10$ K)。样品的掺杂$p$非常接近赝能隙相结束的临界掺杂$p^{\star}$。电阻率与温度呈线性关系,其斜率与普朗克耗散一致。霍尔数$n_{\rm H}$随着$p$的降低而降低,这与载流子密度从高于$p^{\star}$的$n = 1+p$下降到低于$p^{\star}$的$n=p$一致。$n_{\rm H}$的这种下降伴随着从先前的NMR奈特位移测量推断的状态密度的急剧下降。热导率满足Wiedemann-Franz定律,表明$T = 0$中的赝能隙相是一种金属,其费米激发像传统电子一样携带热量和电荷。塞贝克系数在低温下会发生几何发散,这是量子临界性的标志。霍尔热导率在低温下变为负值,表明声子在赝能隙相中是手征的。考虑到在其他非常不同的铜酸盐中观察到这些相同的性质,我们的研究为这五个特征的普适性提供了强有力的证据。

英文摘要:

Five transport coefficients of the cuprate superconductor Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+δ}$ were measured in the normal state down to low temperature, reached by applying a magnetic field (up to 66T) large enough to suppress superconductivity. The electrical resistivity, Hall coefficient, thermal conductivity, Seebeck coefficient and thermal Hall conductivity were measured in two overdoped single crystals, with La concentration $x = 0.2$ ($T_{\rm c}=18$K) and $x = 0.0$ ($T_{\rm c}=10$K). The samples have dopings $p$ very close to the critical doping $p^{\star}$ where the pseudogap phase ends. The resistivity displays a linear dependence on temperature whose slope is consistent with Planckian dissipation. The Hall number $n_{\rm H}$ decreases with reduced $p$, consistent with a drop in carrier density from $n = 1+p$ above $p^{\star}$ to $n=p$ below $p^{\star}$. This drop in $n_{\rm H}$ is concomitant with a sharp drop in the density of states inferred from prior NMR Knight shift measurements. The thermal conductivity satisfies the Wiedemann-Franz law, showing that the pseudogap phase at $T = 0$ is a metal whose fermionic excitations carry heat and charge as do conventional electrons. The Seebeck coefficient diverges logarithmically at low temperature, a signature of quantum criticality. The thermal Hall conductivity becomes negative at low temperature, showing that phonons are chiral in the pseudogap phase. Given the observation of these same properties in other, very different cuprates, our study provides strong evidence for the universality of these five signatures of the pseudogap phase and its critical point.

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。

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