Anisotropic properties of a single superconducting CaCuO2/SrTiO3interface

Salvato, M.; Tieri, Giulio; Balestrino, G.; Castro, D. Di

doi:10.1088/0953-2048/28/9/095012

Cited by 4 publications

(3 citation statements)

References 49 publications

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“…where H c ab 2 and H c c 2 are the upper critical fields along the a-b plane (the plane of the substrate) and the c-axis (perpendicular to the substrate surface), respectively. The resistance as a function of temperature in different magnetic field has been measured in CCO/STO SLs [39] and a CCO/STO bilayer [40]. The results, reported in figure 10, show that the superconducting anisotropy is about three to four times larger in a CCO/STO bilayer (γ≈17-18), where there is no interlayer interaction, than in CCO/STO SLs (γ≈5-7).…”

Section: Cacuo 2 /Srtiomentioning

confidence: 99%

Superconductivity in interacting interfaces of cuprate-based heterostructures

Castro

Balestrino

2018

Supercond. Sci. Technol.

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Low dimensional superconducting systems have been the subject of numerous studies in the recent past, with the aim of achieving a higher and higher critical temperature (T c ). The recent improvement in film deposition techniques has allowed the realization of artificial heterostructures, with atomically flat surfaces and interfaces, where novel properties appear that are not present in the single constituent. For instance, quasi-2D superconductivity was found at the interface between different oxides. In this review we analyze, in particular, the quasi-2D superconductivity occurring at the interface between two non-superconducting oxides, mostly cuprates. Throughout a comparison of the superconducting properties of different oxide heterostructures and superlattices, we propose a phenomenological explanation of the behavior of the T c as a function of the number of conducting CuO 2 planes. This is achieved by introducing two different interactions between the superconducting 2D sheets. This interpretation is finally extended also to standard high T c cuprates, contributing to the solution of the long-standing question of the dependence of T c on the number of CuO 2 planes in these systems.

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Section: Cacuo 2 /Srtiomentioning

confidence: 99%

Superconductivity in interacting interfaces of cuprate-based heterostructures

Castro

Balestrino

2018

Supercond. Sci. Technol.

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“…而得到了穹顶状的 T c -调控电压关系曲线 [52] 。这与之前在薄膜中发现的无序驱动的超导-绝缘体量子相变类似 [53] ，所以他们认为这也是一种由无序驱动的效相近 [55,56] 。但对于 KTO，化学掺杂的 KTO 体材料上并未发现超导，然而研究者们通过电双层(electric double layer ，EDL)晶体管调控，在 KTO(001)表面得到 T c 在 50 mK 左右的超导 [57] ，同时利用离子液体(ionic liquid ，IL 组成，其超导发生在铜氧层上。铜氧化物超导体的母体一般是反铁磁绝缘体 [59] ，可以通过掺杂来压制反铁磁序从而获得超导，但当掺杂量的进一步增加，超导消失，材料进入费米液体态，整个超导区域随着掺杂的变化呈一个穹顶状。对于铜氧化物超导体而言，T c 和单个元胞内铜氧面层数成正相关 [60] ，而且很多铜氧化物超导体的 T c 都远超 BCS 理论所得到的麦克米兰极限，所以一般认为铜氧化物超导体是非常规超导体。同时铜氧化物超导的电子配对对称性也不是常规超导体的 s 波配对，现阶段接受最广泛的是𝑑 𝑥 2 −𝑦 2 配对 [61] 。目前 2DEG 界面超导 T c 最高只有 2. 研究发现其面内和面外的上临界场具有明显的各向异性 [66,67]…”

Section: 一个非常经典的理论：在有杂质的情况下(现实中任何材料都有杂质) ，足够大unclassified

Quasi-two-dimensional superconductivity at oxide heterostructures

Feng¹,

Liang²,

Zhang³

2023

Acta Phys. Sin.

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Oxide interfaces manifest many fascinating phenomena with synergetic correlations among multiple degrees of freedom, including the interplay of broken symmetry, lattice mismatch, charge transfer, spatial confinement, etc. In particular, the interface superconductivity in oxide heterostructures has attracted extensive attention due to the rich underline physics. Interfaces not only provide alternative research platforms with respect to the bulk material counterpart for exploration of new superconductors and investigating superconducting mechanisms, but also create new opportunities for promoting superconductors to future electronic devices. In recent years, thanks to the rapid development of heteroepitaxial techniques and accurate characterization methods, researchers have found quasi-two-dimensional interface superconductivity in various oxide heterostructures and revealed numerous novel quantum phenomena associated with interface superconductivity, which not only promote the development of condensed matter physics, but also lay important foundations for the practical application of interface superconductivity. In this brief review, we mainly focus on the discussion of the quasi-two-dimensional superconductivity at oxide interfaces. Taking the typical quasi-two-dimensional superconductivity at the LaAlO3/SrTiO3 interface and copper oxides such as La2CuO4/La1.56Sr0.44CuO4 as examples, we summarize and examine some novel physical phenomena with interface superconductivity in complex oxide heterostructures. Then we address the related problems that still exist in the research field at present, and finally we look forward to the future possible development of the interface superconductivity.

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“…The effect of interface on superconductivity has received much attention. It was demonstrated that superconductivity can occur at the interface of two nonsuperconducting materials [1][2][3][4][5][6], and the critical temperature (T c ) can even be significantly enhanced com-pared with the corresponding single-phase samples [1,[7][8][9]. One of the most intriguing interfaces is the bilayer of La 2 CuO 4 and La 2−x Sr x CuO 4 [LSCO(x)] films.…”

Section: Introductionmentioning

confidence: 99%

High-temperature interface superconductivity in bilayer copper oxide films by pulsed laser deposition

Den

Ren

et al. 2019

Sci. China Mater.

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In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La 2 CuO 4 and metallic La 2−x Sr x CuO 4 (x=0.45). An interesting question to address is how general and robust this interface superconductivity is. In the past, the cuprate bilayers were grown in a unique atomic-layer molecular beam epitaxy system, with a Sr doping range of x≤0.47, and the atomically flat interface was thought to be indispensable. Here, we have fabricated bilayers of La 2 CuO 4 and La 2−x Sr x CuO 4 by pulsed laser deposition. We have tried to extend the nominal doping range of Sr from the previous maximum of 0.47 to the present 1.70 (the nominal Sr content in the targets). X-ray diffraction result indicates that our La 2−x Sr x CuO 4 films with x≤0.60 have very high crystalline quality; but the film crystalline structure degrades gradually with further increasing x, and finally the structure is fully lost when x reaches 1.40 and higher. Although the film quality scatters dramatically, our experiments show that there exists superconductivity for bilayers in nearly the entire over-doped Sr range, except for a non-superconducting region at x~0.80. These observations demonstrate that the interface superconductivity in copper oxides is very general and robust.

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Anisotropic properties of a single superconducting CaCuO₂/SrTiO₃interface

Cited by 4 publications

References 49 publications

Superconductivity in interacting interfaces of cuprate-based heterostructures

Superconductivity in interacting interfaces of cuprate-based heterostructures

Quasi-two-dimensional superconductivity at oxide heterostructures

High-temperature interface superconductivity in bilayer copper oxide films by pulsed laser deposition

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