Robust dx2−y2 -wave superconductivity of infinite-layer nickelates

Abstract

Motivated by the recent observation of superconductivity in strontium doped NdNiO2, we study the superconducting instabilities in this system from various vantage points. Starting with first-principles calculations, we construct two distinct tight-binding models, a simpler single-orbital as well as a three-orbital model, both of which capture the key low energy degrees of freedom to varying degree of accuracy. We study superconductivity in both models using the random phase approximation (RPA). We then analyze the problem at stronger coupling, and study the dominant pairing instability in the associated t-J model limits. In all instances, the dominant pairing tendency is in the d x 2 −y 2 channel, analogous to the cuprate superconductors. arXiv:1909.03015v2 [cond-mat.supr-con]

Role of 4f states in infinite-layer NdNiO2

“…Pk2 has strong Ni 3d z 2 character as well as some 3d xz,yz influence, considerably stronger than the Nd 5d xy component that has been discussed by several groups. [5][6][7][8][9][10] Due to k z dispersion, the large Ni d x 2 −y 2 FS appears in this folded zone as a large banana centered at M ′ , and strongly fluted cylinders also centered at M ′ and connected by tiny necks at the corner R ′ points. These two surfaces are degenerate along the zone faces reflecting simple folding back into the AFM zone, and correspond to M -centered hole barrels in the primitive zone that are familiar from cuprate physics.…”

“…A number of groups recently have revisited this question, with the objective of few-band model-building to quantify differences related to superconductivity. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] The popular approach has been to obtain the non-magnetic local density approximation (LDA) band structure of NdNiO 2 with the 4f 3 electrons assigned to a non-magnetic core, then approximate the low energy bands with a minimal local orbital model, add a repulsive local interaction, and * Electronic address: mckwan@korea.ac.kr † Electronic address: wepickett@ucdavis.edu evaluate the consequences, viz. the pairing susceptibility.…”

Materials design of dynamically stable d9 layered nickelates

“…The recent discovery of superconductivity in the Srdoped nickelate NdNiO 2 [1] offers a new exciting platform for investigating unconventional superconductivity in layered correlated materials, thus prompting active theoretical and experimental studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Here, one fascinating avenue to explore is computational materials design of new nickelate superconductors exploiting the layered crystal structure.…”

Absence of superconductivity in bulk Nd1−xSrxNiO2

“…Recently, superconductivity was observed at 9 -15 K in the strontium doped infinite-layer nickelate thin films of Nd0.8Sr0.2NiO2 on SrTiO3 substrate [18] . This work has stimulated enormous interests, and plenty of theoretical works have been carried out [19][20][21][22][23][24][25][26][27][28][29][30][31] . Among them, Zhang et al propose the parent compound of Nd0.8Sr0.2NiO2 as a self-doped Mott insulator [26] .…”

“…And they also propose some other promising compounds analogues to high-TC cuprates. Several other groups also studied the dominant pairing instability in the framework of t-J model [23,27] .…”