Specific features of the magnetic properties of RB4 (R = Ce, Sm and Yb) tetraborides. Effects of pressure

Панфилов, А. С.; Grechnev, G. E.; Zhuravleva, I.; Fedorchenko, A. V.; Муратов, В. Б.

doi:10.1063/1.4916067

Cited by 10 publications

(5 citation statements)

References 37 publications

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“…Based on the data obtained in this paper, this type of magnetism is weakly sensitive to changes in the volume of a crystalline cell under pressure, which is also characteristic for other paramagnets of this type, e.g. for SmB 4 [53].…”

Section: Discussionmentioning

confidence: 55%

Magnetic properties of RCoO$_3$ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure

Panfilov,

Lyogenkaya,

Grechnev

et al. 2018

Preprint

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We have investigated the temperature dependence of the magnetic susceptibility χ(T ) of rareearth cobaltites RCoO3 (R= La, Pr, Nd, Sm, Eu) in the temperature range 4.2 − 300 K and also the influence of hydrostatic pressure up to 2 kbar on their susceptibility at fixed temperatures T = 78 and 300 K. The specific dependence χ(T ) observed in LaCoO3 and the anomalously large pressure effect (d ln χ/dP ∼ −100 Mbar −1 for T = 78 K) are analysed in the framework of a two-level model with energy levels difference ∆. The ground state of the system is assumed to be nonmagnetic with the zero spin of Co 3+ ions, and magnetism at a finite temperature is determined by the excited magnetic spin state. The results of the analysis, supplemented by theoretical calculations of the electronic structure of LaCoO3, indicate a significant increase in ∆ with a decrease in the unit cell volume under the hydrostatic pressure. In the series of RCoO3 (R= Pr, Nd, Sm, Eu) compounds, the volume of crystal cell decreases monotonically due to a decrease in the radius of R 3+ ions. This leads to an increase in the relative energy ∆ of the excited state (the chemical pressure effect), which manifests itself in a decrease in the contribution of cobalt ions to the magnetic susceptibility at a fixed temperature, and also in a decrease in the hydrostatic pressure effect on the susceptibility of RCoO3 compounds, which we have observed at T = 300 K.

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Section: Discussionmentioning

confidence: 55%

Magnetic properties of RCoO$_3$ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure

Panfilov,

Lyogenkaya,

Grechnev

et al. 2018

Preprint

Self Cite

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“…The second is the celebrated Shastry-Sutherland Hamiltonian. Interestingly, this problem already lends itself to materials applications and experimental data analysis, for example, it is conjectured to describe the class of rare-earth tetraborides (ErB 4 , TmB 4 and NdB 4 ) and allows a direct comparison with several existing results both theoretical [32][33][34][35][36] and experimental [37][38][39][40][41][42]. The third case is the more complex Ising triangular lattice which represents a maximally frustrated problem in the infinite geometry limit [43,44].…”

Section: Introductionmentioning

confidence: 99%

Simulations of Frustrated Ising Hamiltonians with Quantum Approximate Optimization

Lotshaw,

Xu,

Khalid

et al. 2022

Preprint

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Novel magnetic materials are important for future technological advances. Theoretical and numerical calculations of ground state properties are essential in understanding these materials, however, computational complexity limits conventional methods for studying these states. Here we investigate an alternative approach to preparing materials ground states using the quantum approximate optimization algorithm (QAOA) on near-term quantum computers. We study Ising spin models on unit cells of square, Shastry-Sutherland, and triangular lattices, with varying field amplitudes and couplings in the material Hamiltonian. We find relationships between the theoretical QAOA success probability and the structure of the ground state, indicating that only a modest number of measurements ( < ∼ 100) are needed to find the ground state of our nine-spin Hamiltonians, even for parameters leading to frustrated magnetism. We further demonstrate the approach in calculations on a trapped-ion quantum computer and succeed in recovering each ground state of the Shastry-Sutherland unit cell with probabilities close to ideal theoretical values. The results demonstrate the viability of QAOA for materials ground state preparation in the frustrated Ising limit, giving important first steps towards larger sizes and more complex Hamiltonians where quantum computational advantage may prove essential in developing a systematic understanding of novel materials.

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“…Interestingly, this problem already lends itself to materials applications and experimental data analysis. Among other examples, it is conjectured to describe the class of rare-earth tetraborides (ErB 4 , TmB 4 and NdB 4 ) and allows a direct comparison with several existing results both theoretical [23][24][25][26][27] and experimental [28][29][30][31][32][33]. The third case is the more complex Ising triangular lattice which represents a maximally frustrated problem with an infinite number of possible ground states in the infinite size limit [34,35].…”

Section: Introductionmentioning

confidence: 99%

Simulations of frustrated Ising Hamiltonians using quantum approximate optimization

Lotshaw

Khalid

et al. 2022

Phil. Trans. R. Soc. A.

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Novel magnetic materials are important for future technological advances. Theoretical and numerical calculations of ground-state properties are essential in understanding these materials, however, computational complexity limits conventional methods for studying these states. Here we investigate an alternative approach to preparing materials ground states using the quantum approximate optimization algorithm (QAOA) on near-term quantum computers. We study classical Ising spin models on unit cells of square, Shastry-Sutherland and triangular lattices, with varying field amplitudes and couplings in the material Hamiltonian. We find relationships between the theoretical QAOA success probability and the structure of the ground state, indicating that only a modest number of measurements ( ≲ 100 ) are needed to find the ground state of our nine-spin Hamiltonians, even for parameters leading to frustrated magnetism. We further demonstrate the approach in calculations on a trapped-ion quantum computer and succeed in recovering each ground state of the Shastry-Sutherland unit cell with probabilities close to ideal theoretical values. The results demonstrate the viability of QAOA for materials ground state preparation in the frustrated Ising limit, giving important first steps towards larger sizes and more complex Hamiltonians where quantum computational advantage may prove essential in developing a systematic understanding of novel materials. This article is part of the theme issue ‘Quantum annealing and computation: challenges and perspectives’.

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Specific features of the magnetic properties of RB4 (R = Ce, Sm and Yb) tetraborides. Effects of pressure

Cited by 10 publications

References 37 publications

Magnetic properties of RCoO$_3$ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure

Magnetic properties of RCoO$_3$ cobaltites (R = La, Pr, Nd, Sm, Eu). Effects of hydrostatic and chemical pressure

Simulations of Frustrated Ising Hamiltonians with Quantum Approximate Optimization

Simulations of frustrated Ising Hamiltonians using quantum approximate optimization

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