Dopant size effects on novel functionalities: High-temperature interfacial superconductivity

Suyolcu, Y. Eren; Wang, Yi; Baiutti, Federico; Al-Temimy, Ameer; Gregori, Giuliano; Cristiani, G.; Sigle, Wilfried; Maier, Joachim; Aken, Peter A. van; Логвенов, Г.

doi:10.1038/s41598-017-00539-4

Cited by 27 publications

(35 citation statements)

References 40 publications

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“…This indicates that due to ionic intermixing, i.e., to ionic doping, superconductivity should not be ascribed to effects arising at the M-I interface; rather, it is a bulk phenomenon involving several unit blocks which is also evidenced via previous mutual inductance measurements. [27] In addition, our EELS investigations reveal some interesting ordering of M 2+ dopant elements in the epitaxial layers. Especially in the overdoped region, the EELS elemental maps reveal that the M 2+ O planes just after the CuO 2 planes have a larger dopant concentration, which indicates a broken inversion symmetry in our structures [46] (relatively less clear for Ca doping; please see Figures 2-4).…”

Section: Discussionmentioning

confidence: 93%

“…The superconducting properties of all three metal-insulator (M-I) bilayers were already discussed in detail in a previous study. [27] The temperature dependence of the electrical resistance for all samples is presented in Figure 1e, and all exhibit a superconducting transition with T c of ≈39 K (red), ≈36 K (green), and ≈17 K (blue) for Ba-, Sr-, and Ca-doped bilayers, respectively. The mutual inductance measurement showing the broad superconducting transition of the Ba-doped sample due to the possible variation of T c in different regions of the sample is presented in Figure S3 in the Supporting Information, which is a consequence of inhomogeneous Ba distribution across the interface.…”

Section: Resultsmentioning

confidence: 99%

“…[27] From the EELS investigations, different profiles of dopant distribution for Ba-, Sr-, and Ca-doped bilayers were obtained. Figure 6a-c summarizes the dopant concentrations and gives quantitative information about the composition of each block.…”

Section: Discussionmentioning

confidence: 99%

“…Previous investigations of LCO-based bilayers have been limited to Sr-doped systems [25] or, in the case differently sized dopants have been used, no insights have been gained regarding the local lattice structural parameters. [27] Here, by analyzing the cationic and the anionic deformations with atomic resolution, we show that the size mismatch between the dopant and the host La 3+ cations directly affects the structure and in particular the out-of-plane strain state. [38] We demonstrate that the dopant size locally distorts both cationic (LaLa) and the anionic (OO) sublattice and that different JT distortions are present.…”

Section: Introductionmentioning

confidence: 99%

“…[25,26] Thus, local JT distortions appear to be strongly related to the presence of 2D interfacial superconductivity. Moreover, investigations on La 2−x M x CuO 4 (LMCO)LCO bilayers [27] (where M is a divalent cation M = Ba, Sr, and Ca) and 2D-doped La 2 CuO 4 superlattices [26,28] pointed out that the dopant size and dopant distribution directly influence the interface functionalities, i.e., the occurrence of bulk-like or interfacial superconductivity. In particular, interfacial superconductivity is induced only in the presence of a sharp interface.…”

Section: Introductionmentioning

confidence: 99%

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Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects

Suyolcu

Wang

Sigle

et al. 2017

Adv Materials Inter

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properties of complex perovskite oxide structures are strongly influenced by small structural changes of the BO 6 octahedral network. [2][3][4][5] Impressive examples are heterostructure interfaces for which even small alterations of the octahedral network can give rise to striking changes in the electronic structure [6,7] and induce functional properties such as quantum Hall effect, [8] magnetism, [9] superconductivity, [10,11] ferroelectricity, [12] the formation of 2D free electron gases, [13] and hightemperature interfacial superconductivity (HT-IS). [14] During the last years, these interfacial phenomena have attracted more and more attention not only due to potential applications but also due to the fundamental physics and chemistry aspects of these material systems. [15] For example, tailoring and tuning lattice distortions can be achieved by strain states imposed, e.g., by the lattice mismatch between substrate and film in epitaxial systems. [3,[16][17][18][19] Thus, understanding how octahedral distortions are correlated with dopant distribution and how they modify the functionality of complex oxide heterostructures is of great significance.The Jahn-Teller (JT) effect is a spontaneous geometric distortion of a nonlinear system in an electronic state with orbital degeneracy and results in removing the degeneracy via energy state splitting and lowering its symmetry. [20] Transition metal oxides with octahedral coordination, in which the metal ion has high-spin d 4 , low-spin d 7 , and d 9 configurations, show JT distortions, which can be intimately correlated with the physical properties. [21] For instance, the CuO 6 octahedron in the parent La 2 CuO 4 (LCO) is elongated along the "apical direction" by the JT effect [22] and exhibits two long and four short CuO bonds. [22,23] Distortions of CuO 6 in Sr-doped La 2−x Sr x CuO 4 structures (x up to 0.4) and related changes in CuO apical distances were studied via diffraction techniques providing average structural information. [24] It is reported that, in such systems, increasing the dopant concentration determines the compression of the octahedron (i.e., a decrease of the CuO apical distances) [24] defined as anti-Jahn-Teller (AJT) effect. [22] Recently, it was shown that in the presence of interfacial electronic redistribution leading to a decoupled concentration profile between electron holes and dopant ions (striking interface

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Section: Discussionmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects

Suyolcu

Wang

Sigle

et al. 2017

Adv Materials Inter

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Influence of Chemistry and Misfit Dislocation Structure on Dopant Segregation at Complex Oxide Heterointerfaces

Dholabhai

Martínez

Uberuaga

2018

Advcd Theory and Sims

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Complex oxide heterostructures and thin films have emerged as promising candidates for diverse applications. Lattice mismatch between the two oxides lead to the formation of misfit dislocations, which influence vital material features. Trivalent dopant segregation to misfit dislocations at semi-coherent oxide heterointerfaces, while not well understood, is anticipated to impact interface-governed properties. Here, atomistic simulations elucidating the influence of misfit dislocations on dopant segregation at SrTiO 3 /MgO heterointerfaces are reported. SrO-and TiO 2 -terminated interfaces that have differing misfit dislocation structure were considered for trivalent dopants segregation. At SrO-terminated interface, dopants tend to segregate toward but not precisely to the heterointerface, whereas at TiO 2 -terminated interface, dopants exhibit a thermodynamic preference to accumulate at the heterointerface. Most favorable segregation sites at SrO-terminated interface are located within the coherent terrace, whereas those at TiO 2 -terminated interface are at misfit dislocation intersections. Atomic layer chemistry and the resulting misfit dislocation structure at the heterointerface, along with concomitant strain at the heterointerface due to mismatched dopants, play a critical role in influencing the observed trends for dopant segregation. Overall, the present results offer a fundamental atomic scale perspective of dopant behavior at semi-coherent complex oxide heterointerfaces and the interplay between dopant chemistry, interface chemistry, and misfit dislocation structure.

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Superconductivity at Interfaces in Cuprate‐Manganite Superlattices

et al. 2023

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One of the unsolved problems for using high-T c superconducting cuprates for spintronic applications are the short coherence lengths of Cooper pairs in oxides (a few Å), which requires atomically sharp and defect-free interfaces. This research demonstrates the presence of high-T c superconducting La 1.84 Sr 0.16 CuO 4 in direct proximity to SrLaMnO 4 and provides evidence for the sharpness of interfaces between the cuprate and the manganite layers at the atomic scale. These findings shed light on the impact of the chemical potential at the interface of distinct materials on highly sensitive physical properties, such as superconductivity. Additionally, this results show the high stability of ultrathin layers from the same K 2 NiF 4 -type family, specifically one unit cell of Sr 2−x La x MnO 4 and three unit cells of La 1.84 Sr 0.16 CuO 4 . This work advances both the fundamental understanding of the proximity region between superconducting cuprates and manganite phases and the potential use of oxide-based materials in quantum computing.

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Dopant size effects on novel functionalities: High-temperature interfacial superconductivity

Cited by 27 publications

References 40 publications

Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects

Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects

Influence of Chemistry and Misfit Dislocation Structure on Dopant Segregation at Complex Oxide Heterointerfaces

Superconductivity at Interfaces in Cuprate‐Manganite Superlattices

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Dopant size effects on novel functionalities: High-temperature interfacial superconductivity

Cited by 27 publications

References 40 publications

Octahedral Distortions at High‐Temperature Superconducting La2CuO4 Interfaces: Visualizing Jahn–Teller Effects

Octahedral Distortions at High‐Temperature Superconducting La2CuO4 Interfaces: Visualizing Jahn–Teller Effects

Influence of Chemistry and Misfit Dislocation Structure on Dopant Segregation at Complex Oxide Heterointerfaces

Superconductivity at Interfaces in Cuprate‐Manganite Superlattices

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Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects

Octahedral Distortions at High‐Temperature Superconducting La₂CuO₄ Interfaces: Visualizing Jahn–Teller Effects