Evolution of the Chern Gap in Kagome Magnet HoMn6Sn6−xGex

Sims, Christopher

doi:10.3390/condmat7020040

Cited by 4 publications

(4 citation statements)

References 58 publications

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“…Rare-earth (R) material class RMn 6 Sn 6 displays rich and intricate physical phenomena consisting of strong electron-electron correlations, spin-orbit effects, and supposedly topological behavior [1][2][3][4][5][6][7][8][9][10]. These materials belong to the P 6/mmm (#191) space group, where Mn atoms form 2D kagome layers interlaced with R and Sn layers, see Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…These materials belong to the P 6/mmm (#191) space group, where Mn atoms form 2D kagome layers interlaced with R and Sn layers, see Figure 1. Although RMn 6 Sn 6 family of materials has been studied for more than three decades, recent experimental anomalous Hall effect (AHE) studies [1,9,11] inspired a new wave of research [2][3][4][5][6][7][8][12][13][14][15][16]] on related materials.…”

Section: Introductionmentioning

confidence: 99%

“…However, the possibility of realizing the Chern phase hinges on the ability to align the Fermi level (E F ) in the Dirac crossing (DC), or the Chern gap, seen in the kagome systems [1,2,26]. Yin and coworkers' experiments show that the Chern gap is located at 130 (4) meV above E F [1]. However, Lee and coworkers reported density functional theory with Hubbard U (DFT+U ) calculations [2] predicting the DC to be 700 meV above E F , or at least 300 meV above E F , suggesting that the Dirac crossing cannot be related to the observed AHE signal.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

Annaberdiyev¹,

Mitáš²,

Krogel³

et al. 2023

Preprint

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A member of the RMn6Sn6 rare-earth family materials, TbMn6Sn6, recently showed experimental signatures of the realization of a quantum-limit Chern magnet. Despite the promising experimental results, theoretical studies with accurate electron correlations which probe these observations have been lacking. In this work, we use quantum Monte Carlo (QMC) and density functional theory with Hubbard U (DFT+U ) calculations to examine the electronic structure of TbMn6Sn6. To do so, we optimize accurate, correlation-consistent pseudopotentials for Tb and Sn using coupled-cluster and configuration-interaction (CI) methods. We find that DFT+U and single-reference QMC calculations suffer from the same overestimation of the magnetic moments as meta-GGA and hybrid density functional approximations. Our findings point to the need for improved orbitals/wavefunctions for this class of materials, such as natural orbitals from CI, or for the inclusion of multi-reference effects that capture the static correlations for an accurate prediction of magnetic properties. The necessity for multi-reference treatment is motivated by extrapolating the dynamic correlations to the exact limit. DFT+U with Mn magnetic moments adjusted to experiment predict the Dirac crossing in bulk to be close to the Fermi level, within ∼ 120 meV, in agreement with the experiments. Our nonstoichiometric slab calculations show that the Dirac crossing approaches even closer to the Fermi level, suggesting the possible realization of Chern magnetism in this limit.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

Annaberdiyev¹,

Mitáš²,

Krogel³

et al. 2023

Preprint

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show abstract

“…Fractional Chern Fermions have been observed in van-der-walls heterostructures, however, they need a magnetic field in order to exhibit the fractional hall effect which still exists under the genus of the FQHE [21,22]. Recently, it has been predicted that strongly gapped Kagome lattices can host fractional Dirac fermions without the need for an external magnetic field [23,24]. This work predicts the fractional orbital Chern hall effect, a hall effect with fractional filling which can be observed without the need for an external applied magnetic field.…”

Section: Introductionmentioning

confidence: 99%

The Fractional Orbital Chern Hall Effect

Sims¹

2023

Preprint

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The fractional quantum hall effect (FQHE) is a milestone of modern day physics, its disovery paved the way for the study of fractional charges which do not obey abelian physics. However, all FQHE require an external magnetic field in order for there to be fractionally charged electrons.This work shows a theoretical study of strongly interaction electrons in the Kagome lattice with magnetism. Under optimal conditions, a band gap opens on the surface of the material which hosts fractional Fermions. These fractional Fermions form composite quasi-electrons without the need for external magnetic field. These states are predicted to host the FQHE without the need for an external magnetic field.

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The role of electron correlations in the electronic structure of putative Chern magnet TbMn6Sn6

Annaberdiyev,

Mandal,

Mitas

et al. 2023

npj Quantum Mater.

View full text Add to dashboard Cite

A member of the RMn6Sn6 rare-earth family materials, TbMn6Sn6, recently showed experimental signatures of the realization of a quantum-limit Chern magnet. In this work, we use quantum Monte Carlo (QMC) and density functional theory with Hubbard U (DFT + U) calculations to examine the electronic structure of TbMn6Sn6. To do so, we optimize accurate, correlation-consistent pseudopotentials for Tb and Sn using coupled-cluster and configuration–interaction (CI) methods. We find that DFT + U and single-reference QMC calculations suffer from the same overestimation of the magnetic moments as meta-GGA and hybrid density functional approximations. Our findings point to the need for improved orbitals/wavefunctions for this class of materials, such as natural orbitals from CI, or for the inclusion of multi-reference effects that capture the static correlations for an accurate prediction of magnetic properties. DFT + U with Mn magnetic moments adjusted to the experiment predict the Dirac crossing in bulk to be close to the Fermi level, within ~120 meV, in agreement with the experiments. Our non-stoichiometric slab calculations show that the Dirac crossing approaches even closer to the Fermi level, suggesting the possible realization of Chern magnetism in this limit.

show abstract

Evolution of the Chern Gap in Kagome Magnet HoMn6Sn6−xGex

Cited by 4 publications

References 58 publications

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

The Fractional Orbital Chern Hall Effect

The role of electron correlations in the electronic structure of putative Chern magnet TbMn6Sn6

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