Magnetic Interaction in Doped 2D Perovskite Cuprates with Nanoscale Inhomogeneity: Lattice Nonlocal Effects vs. Superexchange
Round 1
Reviewer 1 Report
V. Gavrichkov and S. Polukeev in their manuscript "Magnetic Interaction in Doped 2D Perovskite Cuprates with Nanoscale Inhomogeneity: Lattice Nonlocal Effects vs Superexchange" submitted to Condensed Matter present an innovative theoretical approach to the physics of stripes which could open new venues in the physics of complexity and functionality in magnetic perovskites. The authors have studied how the superexchange interaction Jij in doped 2D cuprates depends on the lattice nanostructure. They include as an essential feature of the stripes scenario the lattice modulation of a CuO2 layer surrounded by two LaO rock salt layers, with the key role of static undistorted U and distorted D stripe nanostructure, forming a U/D/U ... periodic stripe sequence. The static stripes appear at a transition temperature from the dynamic to the static cases with a spontaneous θ-symmetry breaking with respect to the rotation of all the tilted CuO6 octahedra by an orientation angle in the U and D stripe nanostructure of the CuO2 layer.
This paper shows that the charge and spin nanoscale phase separation can be derived at least qualitatively from the lattice concept of the stripe nature and it discusses the observable consequences. The paper key result is the calculation of superexchange interaction in presence the pseudo Jahn-Teller effect where the observed stripe configurations are classified into a ninth-order symmetric Abelian Group G consisting of two types of stripes U and D rotated at the right angle relative to each other. The stripe charge nanostructure is accompanied by spin inhomogeneity and the high-temperature superconductivity. The range of temperature and doping for the transition to the lattice stripe phase unambiguously indicates that there is a clear connection between the multiscale stripe texture and the quantum coherence of quasiparticles in 2D perovskite high-Tc superconductors
The manuscript is well organized and the results are well presented. Thus it is suitable for publication in Condensed matter in the current version.
Author Response
many thanks for your attention to this work
Reviewer 2 Report
The paper "Magnetic Interaction in Doped 2D Perovskite Cuprates with Nanoscale Inhomogeneity Inhomogeneity: Lattice Nonlocal Effects vs Superexchange" by Gavrichkov and Polukeev provides a reliable theoretical picture on the impact of the inhomogeneous nanostructure of doped 2D cuprates on the magnetic interaction is modified. It presents an innovative approach to the physics of stripes and of the complexity in perovskites, alternative to conventional theories which have failed to reproduce many experimental data.
The text shows the calculation of the super-exchange interaction Jij in doped 2D cuprates in the presence of a local lattice tilting of the CuO4 plaquettes in the CuO2 plane. The formalism and the results provide original and theoretical arguments to support the pseudo Jahn-Teller nature of the spin and charge stripes phase in these cuprates. Actually, the proposed approach demonstrates that in high-Tc cuprates the super-exchange interaction depends on the nature of the stripe lattice structure. In addition authors point out that magnetic and superconducting functionality of doped cuprate perovskites are tuned by strain, which control structural tilts, nanoscale and phase separation. The mechanism contributes to form static stripes of distorted D and undistorted U local lattice conformations as clearly detected by EXAFS experiments.
The charge inhomogeneity, the Fermi level pinning only in p type cuprates and the time reversal symmetry breaking are explained by this approach starting from several structural features available from experimental data.
The text describes and innovative approach to the physics of stripes, which could be successful to describe the physics of complexity in many perovskites.
The text is well written, but it is not easy to read. I'm in favor of its publication, still I strongly recommend authors to rephrase some sentences or reduce the longer ones. Because of the interest, if possible, I suggest also to move some equations in an appendix to make the text readable to a larger audience of readers.
Author Response
1. Comment from reviewer: Because of the interest, if possible, I suggest also to move some equations in an appendix to make the text readable to a larger audience of readers.
Answer from authors: Transferring formulas to a supll or append will lead to a major reworking of the paper itself. Therefore, we limited ourselves to a recommendation for readers who are not interested in the mathematical side of the work between 61 and 62 - th lines:
In Sections II and III, we mainly used a visual graphical representation of the stripe structure and exchange interaction. Readers who are not familiar with the Hubbard operator algebra can just skip deriving Eqs.(\ref{eq:4}) and (\ref{eq:5}) from Eq.(\ref{eq:1}) (see below). They are mathematically equivalent, but the first ones is more convenient to understand the concentration hole dependence of the Jahn-Teller (JT) effect in CuO$_2$ layer.
2. Comment from reviewer: The text is well written, but it is not easy to read. I'm in favor of its publication, still I strongly recommend authors to rephrase some sentences or reduce the longer ones.
Answer from authors:
We checked the English spelling and corrected it a bit:
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…a time…
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If the magnetic interaction is a reliable candidate for being used as a glue for holes~\cite{Scalapino2012}, then how will it change in the inhomogeneous nanostructure of doped 2D cuprates?
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If the magnetic interaction is a reliable candidate which can be used as a glue for holes~\cite{Scalapino2012}, then how will it change in the inhomogeneous nanostructure of doped 2D cuprates?
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However, the dynamical charge and spin nanoinhomogeneous is identified and discussed in current neutron and STM experiments ~\cite{Li2019, Du2020, Tsvelik2019, Chen2022}.
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However, the dynamical charge and spin $nanoinhomogeneities are identified and discussed in current neutron and STM experiments ~\cite{Li2019, Du2020, Tsvelik2019, Chen2022}.
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However, in the $N_-(d^8)$ sector of the doped LSCO, the hole carriers are in the Zhang-Rice singlet state $^1A_{1g}$,~\cite{Zhang1988}, this being a JT state.~\cite{Bersuker1992}
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However, in the $N_-(d^8)$ sector of the doped LSCO, the hole carriers are in the Zhang-Rice singlet state $^1A_{1g}$,~\cite{Zhang1988}, and this is a JT state.~\cite{Bersuker1992}
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The signature of static structure do not depend on experimental timescale ranging from $10^{-6}$s to $10^{-15}$s, but is sensitive to temperature and hole concentration~\cite{Lanzara1999}.
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The signature of the static structure $does not$ depend on the experimental timescale ranging from $10^{-6}$s to $10^{-15}$s, but is sensitive to $the temperature$ and hole concentration~\cite{Lanzara1999}.
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The strip signatures noticeably weaken with decreasing temperature, but are still detected as density waves of hole pairs~\cite{Li2019, Du2020, Tsvelik2019, Chen2022}
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The strip signatures noticeably weaken with the decreasing temperature, but are still detected as density waves of the hole pairs~\cite{Li2019, Du2020, Tsvelik2019, Chen2022}.
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The dynamic quenching magnitude in Eq.(\ref{eq:14}) decreases exponentially with increasing Debye temperature
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The dynamic quenching magnitude in Eq.(\ref{eq:14}) decreases exponentially with the increasing Debye temperature
