arXiv subjects

Jian-Hong She

Publications and source records attributed to Jian-Hong She.

4 recordsLinked to original sources

arXiv2026

Layer-resolved Electronic Structure and Correlation of Low-$n$ Square-planar Nickelates: A DFT+DMFT Prediction of Superconducting Candidates

Multi-layer square-planar nickelates provide a rare platform in which the nominal Ni valence, dimensionality, and layer-resolved electronic structure can be tuned within the same structural family. Recent experiments have found superconductivity in $n=4$--8 $R_{n+1}Ni_nO_{2n+2}$ compounds, with the highest $T_c$ near $n=6$, whereas the more heavily hole-doped $n=3$ member remains nonsuperconducting. Here we propose spacer-layer Cl doping as a route to convert low-$n$ nickelates into superconducting candidates. Compared with changing the layer number $n$, Cl substitution on the spacer-layer oxygen sites offers a chemically natural way to continuously tune the Ni valence while leaving the NiO$_2$ planes largely intact; the lower-$n$ compounds may also be more accessible for synthesis. Using density functional theory combined with dynamical mean-field theory, we show that electron-compensated $n=2$ and $n=3$ La-based nickelates, targeted to the nominal Ni valence of superconducting $n=6$, develop Ni-$d$ correlations comparable to those of superconducting higher-$n$ compounds while preserving the characteristic low-energy Ni-$d$ electronic structure. These results suggest spacer-layer Cl doping as a promising strategy for designing low-$n$ square-planar nickelate superconductors.

cond-mat.supr-con↗

arXiv2026

Electronic structure and correlation of La$_4$Co$_2$NiO$_8$Cl$_2$: a theoretical proposal for a La$_4$Ni$_3$O$_{10}$-like high-temperature superconductor

Based on the discovery of high-temperature superconductivity in the bilayer nickelate La$_3$Ni$_2$O$_7$, several Co-based La$_3$Ni$_2$O$_7$-like materials were theoretically predicted as possible high-temperature superconductors by electron doping. Motivated by these findings and the subsequent discovery of superconductivity in the trilayer nickelate La$_4$Ni$_3$O$_{10}$ under high pressure, we propose and investigate a Co-based La$_4$Ni$_3$O$_{10}$-like material. With electron doping to the high-pressure trilayer cobaltate La$_4$Co$_3$O$_{10}$, using density functional theory combined with dynamical mean-field theory (DFT+DMFT), we find that the resulting compound La$_4$Co$_2$NiO$_8$Cl$_2$ exhibits a crystal structure and a strongly correlated electronic structure similar to those of La$_4$Ni$_3$O$_{10}$ under high pressure. This suggests that this new compound may host high-temperature superconductivity.

cond-mat.str-el↗

arXiv2025

Prediction of several Co-based La$_3$Ni$_2$O$_7$-like superconducting materials

High-temperature superconductivity has been found in Fe-, Ni-, and Cu-based compounds but has remained elusive in Co-based materials. The recent discovery of superconductivity in pressurized bilayer nickelate La$_3$Ni$_2$O$_7$ has renewed interest in related layered systems. Here, we predict several Co-based analogs that may realize similar physics. Electron doping of the high-pressure bilayer cobaltate La$_3$Co$_2$O$_7$ yields LaTh$_2$Co$_2$O$_7$, La$_3$Ni$_2$O$_5$Cl$_2$, and La$_3$Ni$_2$O$_5$Br$_2$, which exhibit closely related crystal structures and strongly correlated electronic states. Random-phase-approximation calculations reveal $s$-wave as the leading pairing symmetry in these compounds.

cond-mat.supr-con↗

arXiv2025

Absence of two-orbital superconductivity in cuprate family: A DFT+DMFT perspective

The recent discovery of high-temperature superconductivity in the bilayer nickelate La$_3$Ni$_2$O$_7$ has spurred intense interest in exploring analogous mechanisms in other transition metal oxides. This raises a pivotal question: can cuprates, as neighbors to nickelates in the periodic table, host similar two-orbital superconductivity? Here, we systematically investigate the electronic structure of a series of designed Ruddlesden-Popper cuprates. Our calculations reveal that the parent compound La$_3$Cu$_2$O$_7$ is a weakly correlated metal, and hole-doping fails to induce strong correlation. We find that the actual valence of the copper cations becomes strikingly pinned around +2.3, far away from the targeted $d^8$ configuration. This valence pinning is attributed to the inherent charge-transfer nature of cuprates. We propose this mechanism as a general principle explaining the robust single-orbital physics consistently observed in the cuprate family, holding true even in materials like the high-$T_c$ superconductor Ba$_2$CuO$_{3+\delta}$ that appear structurally primed for two-orbital activity. Our results therefore conclude that the route towards two-orbital superconductivity is fundamentally obstructed in cuprates, providing a crucial constraint for the future design of high-temperature superconductors.

cond-mat.supr-con↗