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We study the thermally driven spin state transition in a two-orbital Hubbard model with crystal field splitting, which provides a minimal description of the physics of LaCoO3. We employ the dynamical mean-field theory with quantum…

Strongly Correlated Electrons · Physics 2011-06-23 Jan Kunes , Vlastimil Krapek

\lco{} is known for its two-step spin crossover as a function of temperature. Despite efforts spanning over half a century, the origin of this phenomenon is still debated, particularly regarding how the microscopic spin states are involved…

Strongly Correlated Electrons · Physics 2024-11-18 Akihiko Ikeda , Yasuhiro H. Matsuda , Keisuke Sato , Joji Nasu

The temperature evolution of structural effects associated with charge (CO) and spin order (SO) in La$_{1.67}$Sr$_{0.33}$NiO$_{4}$ has been investigated using neutron powder diffraction. We report an anomalous shrinking of the $c/a$ lattice…

Strongly Correlated Electrons · Physics 2015-03-17 A. M. Milinda Abeykoon , Emil S. Božin , Wei-Guo Yin , Genda Gu , John P. Hill , John M. Tranquada , Simon J. L. Billinge

Synchrotron X-ray powder diffraction experiments reveal that the transition from a magnetic intermediate spin (IS) state to a nonmagnetic low-spin (LS) ground state in LaCoO3 normally observed when cooling, manifests itself under pressure…

Materials Science · Physics 2009-11-07 T. Vogt , J. A. Hriljac , N. C. Hyatt , P. Woodward

We employ the combination of the density functional and the dynamical mean-field theory (LDA+DMFT) to investigate the electronic structure and magnetic properties of SrCoO3, monocrystal of which were prepared recently. Our calculations lead…

Strongly Correlated Electrons · Physics 2012-09-25 J. Kuneš , V. Křápek , N. Parragh , G. Sangiovanni , A. Toschi , A. V. Kozhevnikov

We present a study of the structure, the electric resistivity, the magnetic susceptibility, and the thermal expansion of La$_{1-x}$Eu$_x$CoO$_3$. LaCoO$_3$ shows a temperature-induced spin-state transition around 100 K and a metal-insulator…

Strongly Correlated Electrons · Physics 2009-11-10 J. Baier , S. Jodlauk , M. Kriener , A. Reichl , C. Zobel , H. Kierspel , A. Freimuth , T. Lorenz

Spin-state crossover beyond a conventional ligand-field theory has been a fundamental issue in condensed matter physics. Here, we report microscopic observations of spin states and low-energy dynamics through orbital-resolved NMR…

Strongly Correlated Electrons · Physics 2018-01-01 Yasuhiro Shimizu , Takuya Takahashi , Syunpei Yamada , Ayako Shimokata , Takaaki Jin-no , Masayuki Itoh

We studied the Co valences and spin states in electron-doped LaCo$_{1-y}$Te$_{y}$O$_3$ by measuring x-ray absorption spectra and electron spin resonance. The low-temperature insulating state involves the low-spin Co$^{3+}$ ($S=0$) and the…

Magnetization measurements of LaCoO$_{3}$ have been carried out up to 133 T generated with a destructive pulse magnet at a wide temperature range from 2 to 120 K. A novel magnetic transition was found at $B>100$ T and $T>T^{*}=32\pm 5$ K…

Strongly Correlated Electrons · Physics 2016-06-15 Akihiko Ikeda , Toshihiro Nomura , Yasuhiro H. Matsuda , Akira Matsuo , Koichi Kindo , Keisuke Sato

In systems where electrons form both dispersive bands and small local spins, we show that changes of the spin configuration can tune the bands through a Lifshitz transition, resulting in a continuous metal-insulator transition associated…

Strongly Correlated Electrons · Physics 2016-12-28 Bongjae Kim , Peitao Liu , Zeynep Ergönenc , Alessandro Toschi , Sergii Khmelevskyi , Cesare Franchini

We investigate lattice dynamics in LaCoO$_3$ using inelastic neutron and x-ray scattering over $T = 2\mbox{-}650\,\mathrm{K}$, spanning the spin-state crossover at $T_{1} \approx 100\,\mathrm{K}$ and the insulator--metal transition at…

The variational cluster approximation is applied to the calculation of thermodynamical quantities and single-particle spectra of LaCoO3. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact…

Strongly Correlated Electrons · Physics 2015-05-14 R. Eder

We have investigated electronic structures of antiferromagnetic YBaCo_2O_5 using the local spin-density approximation (LSDA) + U method. The charge and orbital ordered insulating ground state is correctly obtained with the strong on-site…

Strongly Correlated Electrons · Physics 2009-10-31 S. K. Kwon , B. I. Min

Hole and electron doped LaCoO3 is studied using dynamical mean-field theory. The one-particle spectra are analyzed and compared to the available experimental data, in particular the x-ray absorption spectra. Analyzing the temporal spin-spin…

Strongly Correlated Electrons · Physics 2013-06-27 P. Augustinsky , V. Krapek , J. Kunes

The electronic structure of the perovskite LaCoO$_3$ for different spin states of Co ions was calculated in the LDA+U approach. The ground state was found to be a nonmagnetic insulator with Co ions in a low-spin state. Somewhat higher in…

Strongly Correlated Electrons · Physics 2008-02-03 M. A. Korotin , S. Yu. Ezhov , I. V. Solovyev , V. I. Anisimov , D. I. Khomskii , G. A. Sawatzky

Spin crossover molecules have recently emerged as a family of compounds potentially useful for implementing molecular spintronics devices. The calculations of the electronic properties of such molecules is a formidable theoretical challenge…

Materials Science · Physics 2015-06-04 Andrea Droghetti , Dario Alfe' , Stefano Sanvito

Our success in description of recent electron-spin-resonance results on Mott insulator LaCoO3, Phys. Rev. B 67 (2003) 172401, lies in taking into account strong electron correlations among d electrons and the relativistic spin-orbit…

Strongly Correlated Electrons · Physics 2009-11-10 R. J. Radwanski , Z. Ropka

LaCoO$_3$ provides a poignant example of a transition metal oxide where the cobalt cations display multiple spin states and spin transitions and which continues to garner substantial attention. In this work, we describe first principles…

Materials Science · Physics 2020-04-22 Alex Taekyung Lee , Sohrab Ismail-Beigi

A vector bosonic field coupled to the electronic spin is treated by means of the continuous-time quantum Monte Carlo method. In the Bose Kondo model with a sub-Ohmic density of states $\rho_{B}(\omega) \propto \omega^{s}$ with s=0.2, two…

Strongly Correlated Electrons · Physics 2013-03-11 Junya Otsuki

We study the ground state quantum spin fluctuations around the N\'eel ordered state for the one-band ($t,U$) Hubbard model on a site-diluted square lattice. An effective spin Hamiltonian, $H_{\rm s}^{(4)}$, is generated using the canonical…

Statistical Mechanics · Physics 2009-06-13 J. -Y. P. Delannoy , A. G. Del Maestro , M. J. P. Gingras , P. C. W. Holdsworth