arXiv subjects

Soo-Yong Lee

Publications and source records attributed to Soo-Yong Lee.

3 recordsLinked to original sources

arXiv2014

Arbitrary Chern number generation in the three-band model from momentum space

A simple, general rule for generating a three-band model with arbitrary Chern numbers is given. The rule is based on the idea of monopole charge-changing unitary operations and can be realized by two types of simple unitary operations on the original Hamiltonian. A pair of monopole charges are required to produce desired topological numbers in the three-band model. The set of rules presented here offers a way to produce lattice models of any desired Chern numbers for three-sublattice situations.

cond-mat.str-el↗

arXiv2014

Zero-energy Bound States in Nodal Topological Lattice

Nodal topological lattice is a form of magnetic crystal with topologically non-trivial spin texture, which further exhibits a periodic array of nodes with vanishing magnetization. Electronic structure for conduction electrons strongly Hund-coupled to such nodal topological lattice is examined. Our analysis shows that each node attracts two localized states which form narrow bands through internode hybridization within the mid-gap region. Nodal bands carry a Chern number under suitable perturbations, suggesting their potential role in the topological Hall effect. Enhancement of the density of states near zero energy observable in a tunneling experiment will provide a signature of the formation of nodal topological lattice.

cond-mat.str-el↗

arXiv2013

Visibility recovery by strong interaction in an electronic Mach-Zehnder interferometer

We study the evolution of a single-electron packet of Lorentzian shape along an edge of the integer quantum Hall regime or in a Mach-Zehnder interferometer, considering a capacitive Coulomb interaction and using a bosonization approach. When the packet propagates along a chiral quantum Hall edge, we find that its electron density profile becomes more distorted from Lorentzian due to the generation of electron-hole excitations, as the interaction strength increases yet stays in a weak interaction regime. However, as the interaction strength becomes larger and enters a strong interaction regime, the distortion becomes weaker and eventually the Lorentzian packet shape is recovered. The recovery of the packet shape leads to an interesting feature of the interference visibility of the symmetric Mach-Zehnder interferometer whose two arms have the same interaction strength. As the interaction strength increases, the visibility decreases from the maximum value in the weak interaction regime, and then increases to the maximum value in the strong interaction regime. We argue that this counterintuitive result also occurs under other types of interactions.

cond-mat.mes-hall↗