Nickelate superconductors—a renaissance of the one-band Hubbard model

Kitatani, Motoharu; Si, Liang; Janson, Oleg; Arita, Ryotaro; Zhong, Zhicheng; Held, Karsten

doi:10.1038/s41535-020-00260-y

Cited by 180 publications

(172 citation statements)

References 57 publications

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“…In this case, the s orbital is filled by holes and leaves half-filled x 2 − y 2 orbital-then holes reside mainly on x 2 − y 2 orbital. This finding suggests that for hole doping, the one-band Hubbard model may be sufficient [32]. This intuitive picture of hole configuration requires the x 2 − y 2 to be nearly half-filled, in other words, it suggests that the ground state is a strong antiferromagnet as in cuprates [11,33].…”

Section: Resultsmentioning

confidence: 97%

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Character of Doped Holes in Nd1−xSrxNiO2

et al. 2021

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We investigate charge distribution in the recently discovered high-Tc superconductors, layered nickelates. With increasing value of charge-transfer energy, we observe the expected crossover from the cuprate to the local triplet regime upon hole doping. We find that the d−p Coulomb interaction Udp makes Zhang-Rice singlets less favorable, while the amplitude of local triplets at Ni ions is enhanced. By investigating the effective two-band model with orbitals of x2−y2 and s symmetries we show that antiferromagnetic interactions dominate for electron doping. The screened interactions for the s band suggest the importance of rare-earth atoms in superconducting nickelates.

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Section: Resultsmentioning

confidence: 97%

“…Increasing α increases the double occupancy D x 2 −y 2 , while the double occupancies in s orbitals are almost absent. Thus, the model reduces in this regime to the one-band Hubbard model [32]. • undoped ■ one hole ▲ two holes…”

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confidence: 99%

Character of Doped Holes in Nd1−xSrxNiO2

et al. 2021

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“…The discovery of superconductivity in doped nickel oxides Nd 0.8 Sr 0.2 NiO 2 [1,2] has attracted intensive interest in both experiment [3][4][5][6][7][8][9][10][11][12][13] and theory [3, because the nickelate might be an analog of the well-known high-T c superconductor, cuprates. Recently, the doping dependence has been explored both theoretically [37] and experimentally [8,9] and the presence of the superconducting dome has been confirmed [8,9]. The maximum superconducting transition temperature T c is about 15 K, not very high compared to that of the high-T c cuprates.…”

Section: Introductionmentioning

confidence: 96%

“…The maximum superconducting transition temperature T c is about 15 K, not very high compared to that of the high-T c cuprates. However, because the Bardeen-Cooper-Schrieffer phonon mechanism cannot explain the observed T c [17], the superconducting mechanism is most likely unconventional, in which the electron correlations play an important role [15,25,37,51]. A recent observation of a d-wave-like superconducting gap also supports this scenario [12].…”

Section: Introductionmentioning

confidence: 98%

Magnetic exchange coupling in cuprate-analog d9 nickelates

Nomura

Nomoto

Hirayama

et al. 2020

Phys. Rev. Research

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Motivated by the recent discovery of superconductivity in doped NdNiO 2 , we study the magnetic exchange interaction J in layered d 9 nickelates from first principles. The mother compounds of the high-T c cuprates belong to the charge-transfer regime in the Zaanen-Sawatzky-Allen diagram and have J larger than 100 meV. While this feature makes the cuprates very different from other transition metal oxides, it is of great interest whether layered d 9 nickelates can also have such a large J. However, one complexity is that NdNiO 2 is not a Mott insulator due to carrier doping from the block layer. To compare the cuprates and d 9 nickelates on an equal basis, we study RbCa 2 NiO 3 and A 2 NiO 2 Br 2 (A denotes a cation with a valence of 2.5+), which were recently designed theoretically by block-layer engineering. These nickelates are free from the self-doping effect and belong to the Mott-Hubbard regime. We show that these nickelates share a common thread with the high-T c cuprates in that they also have a significant exchange interaction J as large as about 100 meV.

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“…Recent STM experiments uncovered a mixed sand d-wave superconducting gap feature on the rough surface of Nd 1−x Sr x NiO 2 thin lms [24], and these results were reproduced by employing ab initio treatment on different terminated surfaces [25,26]. As a summary from theoretical side, three main perspectives on nickelates have been proposed, including the cuprate-like correlated single-Ni-orbital d x 2 −y 2 band [23,25,[27][28][29][30][31][32], the Ni-3d-multiorbital effects [33][34][35][36][37], and the Kondo physics between Ni-3d-orbital and Nd-5dorbital [38][39][40]. So far, consensus has not yet been reached about the superconducting mechanism.…”

Section: Introductionmentioning

confidence: 99%

Pressure-induced monotonic enhancement of Tc to over 30 K in the superconducting Pr0.82Sr0.18NiO2 thin films

Wang

Yang²,

Chen

et al. 2021

Preprint

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The successful synthesis of superconducting nickelate thin films with the highest Tc ~ 15 K has reignited great enthusiasms on this class of potential analogue to high-Tc cuprates suggested decades ago. To pursue higher Tc is always an important task in studying new superconductors. Here we report for the first time the effect of pressure on the superconducting properties of infinite-layer Pr0.82Sr0.18NiO2 thin films by measuring electrical resistivity under various pressures in a cubic anvil cell apparatus. We find that the onset of superconductivity, Tconset, can be enhanced monotonically from ~ 18 K at ambient pressure to ~ 31 K without showing signatures of saturation upon increasing pressure to 12.1 GPa in the presence of liquid pressure transmitting medium. This encouraging result indicates that the Tc of infinite-layer nickelates superconductors can be further raised up by applying higher pressures or strain engineering in the heterostructure films. In addition to the pressure effect, we also discussed the influence of stress/strain on the superconducting properties of the nickelate thin films.

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Nickelate superconductors—a renaissance of the one-band Hubbard model

Cited by 180 publications

References 57 publications

Character of Doped Holes in Nd1−xSrxNiO2

Character of Doped Holes in Nd1−xSrxNiO2

Magnetic exchange coupling in cuprate-analog d9 nickelates

Pressure-induced monotonic enhancement of Tc to over 30 K in the superconducting Pr0.82Sr0.18NiO2 thin films

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