### Abstract

We investigate atomic collapse in pseudospin-1 Dirac material systems whose energy band structure constitutes a pair of Dirac cones and a flat band through the conic intersecting point. We obtain analytic solutions of the Dirac-Weyl equation for the three-component spinor in the presence of a Coulomb impurity and derive a general criterion for the occurrence of atomic collapse in terms of the normalized strength of Coulomb interaction and the angular momentum quantum number. In particular, for the lowest angular momentum state, the solution coincides with that for pseudospin-1/2 systems, but with a reduction in the density of resonance peaks. For higher angular momentum states, the underlying pseudospin-1 wave functions exhibit a singularity at the point of zero kinetic energy. Divergence of the local density of states associated with the flat band leads to an inverse square type of singularity in the conductivity. These results provide insights into the physics of the two-body problem for relativistic quantum pseudospin-1 quasiparticle systems.

Original language | English (US) |
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Article number | 245413 |

Journal | Physical Review B |

Volume | 99 |

Issue number | 24 |

DOIs | |

State | Published - Jun 17 2019 |

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### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Physical Review B*,

*99*(24), [245413]. https://doi.org/10.1103/PhysRevB.99.245413

**Atomic collapse in pseudospin-1 systems.** / Han, Chen Di; Xu, Hong Ya; Huang, Danhong; Lai, Ying-Cheng.

Research output: Contribution to journal › Article

*Physical Review B*, vol. 99, no. 24, 245413. https://doi.org/10.1103/PhysRevB.99.245413

}

TY - JOUR

T1 - Atomic collapse in pseudospin-1 systems

AU - Han, Chen Di

AU - Xu, Hong Ya

AU - Huang, Danhong

AU - Lai, Ying-Cheng

PY - 2019/6/17

Y1 - 2019/6/17

N2 - We investigate atomic collapse in pseudospin-1 Dirac material systems whose energy band structure constitutes a pair of Dirac cones and a flat band through the conic intersecting point. We obtain analytic solutions of the Dirac-Weyl equation for the three-component spinor in the presence of a Coulomb impurity and derive a general criterion for the occurrence of atomic collapse in terms of the normalized strength of Coulomb interaction and the angular momentum quantum number. In particular, for the lowest angular momentum state, the solution coincides with that for pseudospin-1/2 systems, but with a reduction in the density of resonance peaks. For higher angular momentum states, the underlying pseudospin-1 wave functions exhibit a singularity at the point of zero kinetic energy. Divergence of the local density of states associated with the flat band leads to an inverse square type of singularity in the conductivity. These results provide insights into the physics of the two-body problem for relativistic quantum pseudospin-1 quasiparticle systems.

AB - We investigate atomic collapse in pseudospin-1 Dirac material systems whose energy band structure constitutes a pair of Dirac cones and a flat band through the conic intersecting point. We obtain analytic solutions of the Dirac-Weyl equation for the three-component spinor in the presence of a Coulomb impurity and derive a general criterion for the occurrence of atomic collapse in terms of the normalized strength of Coulomb interaction and the angular momentum quantum number. In particular, for the lowest angular momentum state, the solution coincides with that for pseudospin-1/2 systems, but with a reduction in the density of resonance peaks. For higher angular momentum states, the underlying pseudospin-1 wave functions exhibit a singularity at the point of zero kinetic energy. Divergence of the local density of states associated with the flat band leads to an inverse square type of singularity in the conductivity. These results provide insights into the physics of the two-body problem for relativistic quantum pseudospin-1 quasiparticle systems.

UR - http://www.scopus.com/inward/record.url?scp=85068870948&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85068870948&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.99.245413

DO - 10.1103/PhysRevB.99.245413

M3 - Article

AN - SCOPUS:85068870948

VL - 99

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 24

M1 - 245413

ER -