Relativistic effects in the electronic structure for the 3d paramagnetic ions♠
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 the law protection of Phys. Rev. Lett. from 30 May, 1997, LE6925 with the discriminating decision of Editor-in-Chief M. Blume of March 7, 2000; put 9 July 1999 to arXiv:cond-mat/9907140; the main results published in Acta Phys. Pol. A 97, 963 (2000); First-principles description of NiO – see Acta Physica 1 (2006) 26; published 30 September 2008; online: www.actaphysica.eu)
It has been shown that relativistic spin-orbit effects have enormous influence on the electronic structure of the correlated electron systems 3dn. The s-o coupling produces the fine electronic structure with a large number of low-energy, <10 meV, localized states. These states affect enormously electronic and magnetic properties of 3d-ion compounds at low- and room-temperature regions. It is inferred that the relativistic s-o effects and the multiplet structure on individual atoms are indispensable for the proper evaluation of the electronic structure of paramagnetic 3d-ion compounds.
PACS: 71.70.E, 7S.10.D, 75.30.Gw;
Keywords: relativistic spin-orbit effects, magnetic moment, crystal field, 3d system, spin-orbit coupling
Why it has been written
Why a paper to Phys. Rev. Lett.: ”Relativistic effects in the electronic structure for the 3d paramagnetic ions” has been written and WHY WE DO CHALLENGE Phys. Rev. Lett. and Phys. Rev. B? − steps of a scientific discrimination in Phys. Rev. Lett. and Phys. Rev. B.
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Discrimination in Physics established by the Editor-in-Chief of Phys. Rev. Lett. Dr M. Blume [ActAPhysica 14-15 (2008) 24-26]
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Almost non-magnetic ground state of the V4+ ion: the case of BaVS3
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 law and scientific protection of Phys. Rev. Lett. from 11 September 2000, LW7315; arXiv:cond-mat/0010135v1, 9 October 2000; related to Acta Physica 14-15 2008; published 31 December 2008; online: www.actaphysica.eu)
We have shown that the V4+ ion with 1 d electron can have almost non-magnetic ground state under the action of the octahedral crystal field in the presence of the spin-orbit coupling and off-cubic distortions. Such the situation occurs in the hexagonal BaVS3. The fine discrete electronic structure with the weakly-magnetic Kramers-doublet ground state is the reason for anomalous properties of BaVS3.
PACS: 71.70.E, 75.10.D
Keywords: crystal-field, spin-orbit, orbital moment
Comment on Phys. Rev. B ”Orbitally driven spin pairing in the three-dimensional nonmagnetic Mott insulator BaVS3: Evidence from single-crystal studies” – wrong description of the V4+ ion
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
(under law and scientific protection of Phys. Rev. B from 22 December 2000, BZK712; written after rejection of our submission to Phys. Rev. Lett. LW7315, see Acta Physica 25, 1 (2008); published 31 December 2008; online: www.actaphysica.eu)
PACS: 75.10.D, 75.30.Gw;
Keywords: 3d compounds, crystal field, spin-orbit coupling
Comment on Phys. Rev. B ”Electronic structure, phase stability, and magnetic properties of La1−xSrxCoO3 from first-principles full-potential calculations” – the neglect of the orbital moment
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
(under law and scientific protection of Phys. Rev. B from 16 August 2000, BVK714; published 31 December 2008; online: www.actaphysica.eu)
In Ref. [1] Ravindran et al. have presented generalized-gradient- corrected, relativistic first-principles full-potential density functional calculations for LaCoO3.
By this Comment [2] we would like to point out that there is a text- book knowledge [3] that the Co3+ ion should be considered as the system with S=2 and L=2, but not as the system with S=2 or S=0 only. Ac- cording to us the orbital magnetism has to be taken into account for the understanding of properties of LaCoO3.
Authors of Ref. 1 write that ”In the cubic perovskites, the octahedral ligand field produced by the O atoms surrounding each Co atom split the tenfold degenerate d levels of Co …” (p. 16426, left column). It is not true as the lowest term of the Co3+ ion in the octahedral field is 25-fold degenerated [4–7], see also [2] and [3]. The statement of Ref. 1 is valid only for the single d electron, but not for 6 d electrons existing in the Co3+ ion.
We fully agree with the authors of Ref. 1 that ”the present (i. e. of Ref. [1]) theory is unable to predict the semiconducting state of LaCoO3” (p. 16426, right column), i.e. the insulating state at 0 K. Moreover, we can add that also thermodynamics cannot be calculated within the approach of Ref. [1].
The existence of the fine electronic structure in LaCoO3
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
(under law and scientific protection of Phys. Rev. B from 10 February 1999, BBR734BJ; arXiv:cond-mat/0005505v1, 29 May 2000; for final our description of LaCoO3 see to our Phys. Rev. B 67, 172401 (2003), published 31 December 2008; online: www.actaphysica.eu)
We argue that in LaCoO3 exists the fine electronic structure associated with the atomic-like states of the Co3+ ions and caused by the crystal-field, the orbital magnetism and intra-atomic spin-orbit interactions. This low-energy fine electronic structure has to be taken into account for any meaningful analysis of electronic and magnetic properties of LaCoO3. In our atomic-like approach the d electrons form the strongly-correlated system 3dn, 3d6 in case of the Co3+ ion in LaCoO3, and have the discrete energy spectrum in contrary to the band picture that yields the continuous energy spectrum. Our studies indicate that the orbital moment has to be unquenched in the description of all 3d-ion compounds.
PACS: 75.10.Dg; 71.70.Ej
Keywords: Mott insulators, crystal-field interactions, magnetic properties, electronic structure.
Preservation of the individuality of 3d atoms in a solid
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Z. Ropka
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
(under law and scientific protection of Phys. Rev. Lett. LL7701 from 30 June 1999 and of Phys. Rev. B from 9 June 2001; arXiv:cond-mat/0006092v1, 6 June 2000; related to: Acta Physica 2 (2007) 1; published 31 December 2008; online: www.actaphysica.eu)
On basis of analysis of experimental results for more than 200 compounds with 3d and 4f elements we conjecture that atoms with unfilled 3d and 4f shells preserve much of their atomic properties, manifested by the discrete electronic structure, even then when they become the part of a solid. As a consequence, electronic and magnetic properties of the 3d-ion containing compounds are strongly affected by the existence of the atomic-like crystal-field fine electronic structure.
PACS: 71.10.-w; 75.10.Dg
Keywords: 3d compounds, strongly-correlated electron systems, crystal field
Crystal-field interactions in LaMnO3 and in GaMnN: evidence for an applicability of the point-charge model
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 law and scientific protection of Phys. Rev. Lett. and Phys. Rev. B from 21 November 2008, LY11532; published 31 December 2008; online: www.actaphysica.eu)
We have shown that energy values of the d − d splittings of 2.06 eV in LaMnO3 and 1.41 eV in Mn-doped GaN can be consistently explained within the ordinary crystal-field theory. Moreover, these values can be calculated from the ordinary point-charge model with the O2- and N3-ions with (r4u) as 17.4 a4D.
PACS: 71.55.Eq; 71.70.Ch;
Keywords: crystal field, 3d compounds, LaMnO3, GaMnN, Mn-doped GaN
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Conventional interactions and the Pr4+-ion states in PrO2
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 31 December 2008, LZ11867; received 10 March 2009; published 31 May 2009; online: www.actaphysica.eu)
We have pointed out the scientific importance of the experimental clarifying (Phys. Rev. Lett. 86 (2001) 2082) of the electronic state of the Pr ion in PrO2 and the role of the intermediate valence and the covalent bonding. We have pointed out the substantial applicability of the crystal-field (CEF) model to PrO2 (the existence of well-defined atomic-like states of the Pr4+ ion) and that the simple point charge model provides surprisingly good estimates for the sign and the strength of the octupolar CEF interactions.
PACS: 71.70.Ch, 75.10.Dg
Keywords: crystal field, point charge model, Pr4+ ion, PrO2
Cubic crystal-field states of the Yb3+ ions studied by specific-heat experiments♠
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 law protection of J. Phys. Cond. Matter from April 7, 1997 CM/83199/Let and CM/84605/PAP; received 31 May 2007; online: www.actaphysica.eu)
Temperature dependence of the specific heat cf (T) of the trivalent ytterbium ions have been examined for different energy level schemes realized under the action of cubic crystal-field interactions. The position of the quartet Γ8 state very strongly influences the temperature course of cf (T). In case of weak spin-dependent interactions, the case very often met in ytterbium compounds, a large specific heat is expected to occur at low temperatures due to the removal of the Kramers degeneracy. The energy level scheme for the Yb3+ ion in YbPdSb with the doublet Γ6 ground state and the quartet state Γ8 as the highest state has been derived reconciling all-known experimental results.
PACS: 71.70; 65.40.H; 75.10.D
Keywords: specific heat, crystal field splitting, ytterbium compounds, YbPdSb
Electronic structure of the V3+ ion in V2O3♠
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
(presented at SCES-02; under law and scientific protection of the Rector of Jagiellonian University, AGH Technical University and to the Polish Academy of Sciences from January 23, 2003; ArXiv:cond-mat/0303194, 11 March 2003; related to Physica B 378-380 (2006) 301 published 31 May 2009; online: www.actaphysica.eu)
We have attributed magnetism and electronic structure of V2O3 to the V3+ ions. We claim that the V3+ ion in V2O3 should be considered as described by the quantum numbers S=1 and L=3. Such quantum numbers result from two Hund’s rules. The resulting electronic structure is much more complex than considered up to now, but it describes, e.g. the insulating ground state and the lowered magnetic moment, of 1.2 μB. It turns out that the intra-atomic spin-orbit coupling is indispensable for the physically adequate description of electronic and magnetic properties of V2O3.
PACS: 71.70.E, 75.10.D, 75.30.Gw
Keywords: highly-correlated electron system, crystal field, V3+ ion, spin-orbit coupling, Mott insulators
Comment on A. M. Oles Phys. Stat. Sol. (b) paper (V2O3) ”Orbital ordering and orbital fluctuations in transition metal oxides”
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
(submitted to Phys. Stat. Sol. (b) on 28 June 2004, a shorter version has been published in Phys. Stat. Sol. (b) 242 (2005) 962; arXiv:cond-mat/0409777v1 30 Sept 2004 received 11 June 2005; online: www.actaphysica.eu)
We argue that the 3A2 state considered by A. M. Oles in Phys. Stat. Sol. (b) 236 (2003) 281 for the d2 system occurring in the V3+ ion in V2O3 and LaVO3 as well as in Ti2+ ion in TiO and in many other oxides is wrong. The proper ground state is 3T1g – its 9-fold degeneracy is further split in a crystal by intra-atomic spin-orbit interactions and lattice distortions.
PACS: 75.10, 75.30
Keywords: crystal field, ground V3+ ion, d2 system, spin-orbit coupling, V2O3
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Wykaz jednostek naukowych z Fizyki i przyznane dotacje na podstawową działalność statutową na rok 2008
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Comment on Phys. Rev. Lett. paper: ”Metal-Ligand interplay in strongly correlated oxides: A parametrized phase diagram for pressure-induced spin transitions” – the strength of the crystal field in NiO.
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 law and scientific protection of Phys. Rev. Lett. from 6 March 2009, LCK1051; published 31 July 2009; online: www.actaphysica.eu)
By this Comment we would like to express our deep scepticism about the strength of the crystal-field parameter in NiO taken in Ref. [1] into calculations, 10Dq of 0.3 eV (Table 1). We claim that this value is more than 3.5 times too small. We claim that the correct value of 10Dq in NiO is 1.09 eV. We would suppose that the value of 10Dq does not influence the high energy spectra.
Comment on Phys. Rev. Lett. paper: ”Revisiting the valence-band and core-level photoemission spectra of NiO” – the strength of the crystal field in NiO.
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
Institute of Physics, Pedagogical University, 30-084 Krakow, Poland
(reprint ActAPhysica 23-24 (2008) 29, under the law protection of Phys. Rev. Lett. from 22 July, 2008, LUK1036; related to Acta Phys. Pol. A 97, 963 (2000); First-principles description of NiO – see Acta Physica 1 (2006) 26; published 31 July 2009; online: www.actaphysica.eu)
By this Comment we would like to express our deep scepticism about the strenght of the crystal-field parameter in NiO taken in Ref. [1] into calculations, 10Dq of 0.3 eV (Fig. 1). We claim that this value is more than 3.5 times to small. We claim that the correct value of 10Dq in NiO is 1.09 eV. We would suppose that the value of 10Dq does not influence the high energy spectra.
Comment on Phys. Rev. B paper: ”Surface effects in the Ni 2p x-ray photoemission spectra of NiO” – the strength of the crystal field in NiO.
R. J. Radwanski∗
Center of Solid State Physics; SntFilip 5, 31-150 Krakow, Poland
(reprint ActAPhysica 23-24 (2008) 28, under the law protection of Phys. Rev. B from 6 June, 2008, BTK1007; related to Acta Phys. Pol. A 97, 963 (2000); First-principles description of NiO – see Acta Physica 1 (2006) 26; published 31 July 2009; online: www.actaphysica.eu)
By this Comment we would like to express our deep scepticism about the strength of the crystal-field parameter in NiO taken in Ref. [1] into calculations, 10Dq of 0.1 eV. This value is written twice, in Table 1 and on page 3, right column top. We claim that this value is more than 10 times to small. We claim that the correct value of 10Dq in NiO is 1.08 eV.
CHALLENGE Phys. Rev. Lett. and Phys. Rev. B on NiO
President of the American Physical Society Prof. Cherry A. Murray
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Crystal field and orbital magnetism as a Polish contribution to the world physics – Quantum Atomistic Solid State Theory – Magnetic Phase Transitions described at the atomic scale (NiO, UPd2Al3)
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
(abstract submitted 10 July 2009 to Polskie Tow. Fizyczne – condensed matter 6 – 11 September, 2009 Krakow, Poland; published 31 July 2009; online: www.actaphysica.eu)
Theoretical description of magnetic, electronic and spectroscopic properties as well as the electronic structure of compounds containing transition-metal atoms is still a subject of strong debate within the modern solid-state physics community. Even magnetic and insulating properties of monoxides FeO, CoO and NiO are not yet well theoretically understood, despite a fact that these compounds form the simple crystallographic structure (NaCl) and the simple antiferromagnetism (TN of 191 K, 291 and 525 K, respectively). In compounds like YbRh2Si2 or UPd2Al3, despite of the heavy-fermion and metallic behaviour, localized states have been recently detected.
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