Jun-Won Rhim

Landau level quantization and almost flat modes in three-dimensional semimetals with nodal ring spectra

We investigate novel Landau level structures of semi-metals with nodal ring dispersions. When the magnetic field is applied parallel to the plane in which the ring lies, there exist almost non-dispersive Landau levels at the Fermi level (E_F = 0) as a function of the momentum along the field direction inside the ring. We show that the Landau levels at each momentum along the field direction can be described by the Hamiltonian for the graphene bilayer with fictitious inter-layer couplings under a tilted magnetic field. Near the center of the ring where the inter-layer coupling is negligible, we have Dirac Landau levels which explain the appearance of the zero modes. Although the inter-layer hopping amplitudes become finite at higher momenta, the splitting of zero modes is exponentially small and they remain almost flat due to the finite artificial in-plane component of the magnetic field. The emergence of the density of states peak at the Fermi level would be a hallmark of the ring dispersion.

Bulk-boundary correspondence from the intercellular Zak phase

The Zak phase

Anisotropic density fluctuations, plasmons, and Friedel oscillations in nodal line semimetal

\ensuremath{\gamma}

Unified bulk-boundary correspondence for band insulators

, the generalization of the Berry phase to Bloch wave functions in solids, is often used to characterize inversion-symmetric one-dimensional (1D) topological insulators. Due to its dependence on the real-space origin and unit cell, however, there is an ambiguity in its use in a bulk-boundary correspondence. Here, we extract an origin-independent part of

Determination of the band parameters of bulk 2H-MX2 (M = Mo, W; X = S, Se) by angle-resolved photoemission spectroscopy

\ensuremath{\gamma}

Nodal-line semimetals from Weyl superlattices

, the so-called intercellular Zak phase

Self-similar occurrence of massless Dirac particles in graphene under a magnetic field

{\ensuremath{\gamma}}^{\mathrm{inter}}

Quantitative analysis on electric dipole energy in Rashba band splitting.

, and show that it is a bulk quantity that unambiguously predicts the number of surface modes. Specifically, a neutral finite 1D tight-binding system has

Quantum oscillations in the Luttinger model with quadratic band touching: Applications to pyrochlore iridates

{n}_{s}={\ensuremath{\gamma}}^{\mathrm{inter}}/\ensuremath{\pi}

Analytical theory of strongly correlated Wigner crystals in the lowest Landau level

(mod 2) in-gap surface modes below the Fermi level if there exists a commensurate inversion-symmetric bulk unit cell. We demonstrate this in two steps: First, we verify that