The claim in Barkman et al [Physical Review Letters {\bf 122}, 165302 (2019)] that pair-density wave (PDW) superconductivity in magnetic field is more stable near surface than in bulk, is not supported by microscopic theory.
The recent Comment by Vorontsov [arXiv:2007.13696] claims that surface pair-density-wave superconductivity with critical temperature higher than the bulk FFLO critical temperature is not supported by microscopic theory. The conclusion is reached by using an approximate semi-microscopic quasiclassical approach. Here we show that a fully microscopic approach unambiguously demonstrates the existence of surface pair-density-wave superconductivity.
Comment on "Novel Superfluidity in a Trapped Gas of Fermi Atoms with Repulsive Interaction Loaded on an Optical Lattice"
在最近的一封信中,Machida et al. [Phys. Rev. Lett. 93,200402(2004)]得出结论,在具有排斥相互作用的费米子的被捕获气体中,超流相出现在陷阱中心的莫特绝缘体周围。他们的结论基于负结合能,以及由位于莫特绝缘体两侧的粒子形成的单线态的大权重。我们在这里表明,所观察到的效果是不相关的超流性。
Evolution of the Superfluid Density in Infinite-Layer Nickelates
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory(斯坦福材料能源科学研究所,SLAC国家加速器实验室);Department of Physics, Stanford University(斯坦福大学物理系);Department of Applied Physics, Stanford University(斯坦福大学应用物理系);Department of Physics and Astronomy, University of Rochester(罗切斯特大学物理与天文学系)
Effect of thermal phase fluctuations on the superfluid density of two-dimensional superconducting films
在0.4 K ~ Tc范围内对Mo_(77)Ge_(23)薄膜的复薄层电导率进行了高精度测量。在低于平均场转变温度Tco的温度Tc处,观察到逆薄层电感1/L(T)的急剧下降。就在Tc以下,1/L(T)被抑制到其平均场值以下,表明纵向相位起伏几乎具有其全部经典振幅,但它们随着T的减小而迅速消失。我们认为,有一个量子交叉在约0.94 Tco,低于经典的相位波动被抑制。
Reply to Comment by Calandra et al on "Electronic Structure of Superconducting KC$_8$ and Nonsuperconducting LiC$_6$ Graphite Intercalation Compounds: Evidence for a Graphene-Sheet-Driven Superconducting State"
Comment on "High Field Quasiparticle Tunneling in Bi_2Sr_2CaCu_2O_{8+δ} : Negative Magnetoresistance in the Superconducting State" (N.Morozov et al, Phys.Rev. Lett. 84,1784 (2000))
Local measurement of the superfluid density in the pnictide superconductor Ba(Fe$_{1-x}$Co$_{x}$)$_2$As$_2$ across the superconducting dome
我们使用局部技术测量Ba(Fe $_{1-x}$ Co $_{x}$)$_2$ As $_2$中的渗透深度$λ_{ab}(T)$,该技术不对样品求平均值。超流密度$ρ_s(T)\equiv1/λ_{ab}(T)^2$具有三个主要特征。首先,$ρ_s(T=0)$在圆顶的欠掺杂侧急剧下降。第二,$λ_{ab}(T)$在最佳掺杂下在低$T$下是平坦的,表明完全带隙的超导性,但在欠掺杂和过掺杂样品中变化更强烈,与幂律或小的第二间隙一致。第三,$ρ_s(T)$在$T_c$附近急剧变化以获得最佳掺杂和欠掺杂。这些观察结果与磁相和超导相之间的相互作用是一致的。
We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for highly unconventional superconducting states with the coexistence of chiral d-wave superconductivity, charge density waves and pair density waves in the strained graphene. Our results show that the strain-induced flat bands can promote the superconducting transition temperature approximately $50\%$ compared to that of the original doped graphene, which suggests that the flat-band superconductivity is a potential route to get superconductivity with higher critical temperatures. In particular, we…
Comment on ''Superconducting decay length in a ferromagnetic metal''
在Gusakova、Kupriyanov和Golubov的论文“Superconducting decay length in a ferromagnetic metal”[Pis'ma v ZhETF 83,487(2006); cond-mat/0605137],作者声称,他们解决了S/S铁磁区的线性化Eilenberger方程,本文指出了作者提出的解是不正确的,并详细解释了我们在较早的文献中找到的精确解工作几年前(物理评论B 64,134506,(2001)。
Comment on "Vortices induced in a superconducting loop by asymmetric kinetic inductance and their detection in transport measurements"
G. R. Berdiyorov,M. V. Milosevic和F. M. Peeters [Phys.Rev.B81,144511(2010)]从理论上研究了超导回路的动态特性。作者认为他们对非对称环的考虑与我们在这一领域的实验结果有关。我们指出这种说法是不正确的,并简要地解释了我们对非对称超导环的测量结果的真正矛盾本质。
Comment on: "Vortex-assisted photon count and their magnetic field dependence in single-photon superconducting detectors" by L.N. Bulaevskii, M.J. Graf and V.G. Kogan, Phys. Rev. B 85, 014505 (2012)
Comment on ``London Theory for Superconducting Phase Transitions in External Magnetic Fields: Application to $\text{UPt}_{3}$''
Letter PRL 89,017004(2002)的作者预测了在低磁场下A相和B相之间的超导转变附近UPt3中的非平凡通量晶格结构,这是激励未来实验的重要结论。我们表明,这封信的方法和结论是错误的。在混合态中不同超导相之间的转变被指出是交叉而不是真正的二阶相变内的最流行的理论模型的双组分超导序参量为UPt3。
A Comment on ``Superconducting-Normal Phase Transition in (Ba1-xKx)BiO3, x = 0.40, 0.47'' by B. F. Woodfield, D. A. Wright, R. A. Fisher, N. E. Phillips and H. Y. Tang, Phys. Rev. Lett. 83, 4622 (1999)
Vortex Fluctuations in the Critical Casimir Effect of Superfluid and Superconducting Films
用涡环重整化方法计算了超流膜中临界Casimir力的大小。当热涡环的大小与薄膜厚度相当时,力变得明显,并且T Tc的结果< Tc are found to match very well with perturbative renormalization theories that have only been carried out for T >。当施加到连接到大块样品的高Tc超导膜时,卡西米尔力导致膜和大块之间出现电压差,估计表明这可能是容易测量的。
Magnetic penetration-depth measurements of a suppressed superfluid density of superconducting Ca$_{0.5}$Na$_{0.5}$Fe$_2$As$_2$ single crystals by proton irradiation
本文报道了质子辐照产生的随机点缺陷对超导Ca $_{0.5}$ Na $_{0.5}$ Fe $_2$ As $_2$单晶超流密度$ρ_{s}$的显著影响。抑制的大小是通过使用磁力显微镜测量与温度相关的磁穿透深度$λ(T)$来推断的。我们的研究结果表明,辐射剂量为2 $\times10^{16}$ cm $^{-2}$由3 MeV的质子产生的超导临界温度$T_{c}$的减少约10%的结果。%,而上临界场的斜率没有明显的变化。相反,$ρ_{s}(0)$被抑制约60%。Abrikosov-Gorkov理论的这种崩溃可以用所谓的“瑞士奶酪模型”来解释,该模型解释了类似于瑞士奶酪中的孔的点缺陷附近的序参数的空间抑制。上临界场的斜率和穿透深度$λ(T/T_{c})/λ(0)$在辐照前后表现出相似的温度依赖性。这可能是由于Ca $_{0.5}$ Na $_{0.5}$ Fe $_2$ As $_2$的高度无序性质与大的带内和同时带间散射以及短相干长度超导性的$s^\pm$波性质的组合。
High-$T_c$ Berezinskii-Kosterlitz-Thouless transition in 2D superconducting systems with coupled deep and quasi-flat electronic bands with van Hove singularities