LaCo0₃ – from first principles

R. J. Radwanski∗
Center of Solid State Physics; Snt. Filip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
Z. Ropka
Center of Solid State Physics; Snt. Filip 5, 31-150 Krakow, Poland
(under law and scientific protection of Phys. Rev. Lett. from 23 March 2006, LQ10665; arXiv: cond-mat/0603619; received 10 December 2006; published 30 April 2010; online: www.actaphysica.eu)

LaCoO₃ from first principles, assuming the atomistic construction of matter and the electrostatic origin of the crystal-field splitting. In our atomic-like approach QUASST the d electrons of the Co³+ ion in LaCoO₃ form the highly-correlated atomic-like system 3d⁶ with the singlet ground state ¹A₁ (an octahedral subterm from the ¹J term) and the excited octahedral subterm ⁵T_2g of the ⁵D term. In the spin-orbital

space, being physically adequate, this high-spin state is Jahn-Teller active. We take the ESR experiment of Noguchi et al., Phys. Rev. B 66, 094404 (2002), as confirmation of the existence of the discrete electronic structure for 3d electron states in LaCoO₃ in the meV scale postulated in QUASST.

 PACS: 76.30.Fc; 75.10.Dg

Keywords: electronic structure, crystal field, spin-orbit coupling, LaCo03

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Comments as consequence of discrimination by Phys. Rev. Lett.

R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland

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Comment on a Phys. Rev. Lett. paper: ”Nanomagnetic droplets and implications to orbital ordering in La_1−xSr_xCoO₃”: the origin of the excited state in LaCoO₃ (LQK1020)

R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
(under the author’s right protection of the American Physical Society from March 28, 2006 LQK1020 – rejected, see following article, pp 14-32; cond-mat/0603812 30 March 2006; published 29 January 2007 in Acta Physica 2 (2007) 24-26; online: www.actaphysica.eu)

In contrary to a claim of the recent Phys. Rev. Lett. 96 (2006) 027201 paper we maintain that the first excited state in LaCoO₃ is the high-spin (HS) state (a lowest quasi-triplet from the octahedral subterm 5T_2g of the 5D term, Phys. Rev. B 67 (2003) 172401) in agreement with the Tanabe-Sugano diagram.

 PACS: 75.10.Dg; 71.70.Ch;

Keywords: 3d compounds, electronic structure, crystal field, spin-orbit coupling, LaCoO₃

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IS as the first excited spin-state in LaCoO₃

D. Louca

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Report of DAE in favour of Radwanski

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Comment on a Phys. Rev. Lett. paper “Spin State Transition in LaCoO₃ studied using Soft X-ray absorption spectroscopy and Magnetic Circular Dichroism”: physics of LS, IS and HS spin states (LAK1030)

R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
(under protection of the American Physical Society from January 3, 2007 (Phys. Rev. Lett. LAK1030 – rejected, see following article pp 35-41) published 30 April 2007 in Acta Physica 5 (2007} 35-36)

We argue that the energy level diagram of a CoO₆ cluster presented in Fig. 2 in the recent Phys. Rev. Lett. 97 (2006) 176405 paper is physically inadequate to LaCoO₃ and that the description of the HS, IS and LS spin states in LaCoO₃ is oversimplified.

PACS: 75.10.Dg: 71.70.

Keywords: spin states, crystal field, LaCo03, 3d compounds

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Evidence of discrimination in Phys. Rev. Lett

R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland

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Comment on Phys. Rev. Lett. 97, 176405: “Spin State Transition in LaCoO₃“: wrong physics of LS, IS and HS spin states

Z. Ropka
Center of Solid State Physics; Snt. Filip 5, 31-150 Krakow, Poland
R. J. Radwanski∗
Center of Solid State Physics; Snt. Filip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland

(under the author’s right protection of the American Physical Society, sent 5 February 2007 to Phys. Rev. Lett., published 30 April 2010; online: www.actaphysica.eu)

PACS: 75.10.Dg: 71.70.Ej

Keywords: 3d oxides, spin states,crystal field, LaCoO₃

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Disagreement for discrimination in physics in the XXI century

R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
(presented at the EPS 2008 Meeting of Condensed Matter Division of the European Physical Society, Rome August 2008 received 30 September 2008; published 30 April 2010; online: www.actaphysica.eu)

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Declaration to Polish Academy of Sciences about important contribution to understanding of magnetic and electronic properties of 3d ion oxides (1997)

Zawiadomienie Polskiej Akademii Nauk o istotnym wkładzie w zrozumienie elektronowych i magnetycznych własności tlenków zawierających jony 3d (z grupy żelaza)

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