832 citations · 2.3k across the 20 of their papers we have counts for
20 papers
Stable topological phase transitions without symmetry indications in NaZnSbBi
Jaemo Jung, Dongwook Kim, Youngkuk Kim
We study topological phase transitions in tetragonal NaZnSbBi, driven by the chemical composition . Notably, we examine mirror Chern numbers that change without symm…
Replica Higher-Order Topology of Hofstadter Butterflies in Twisted Bilayer Graphene
Sun-Woo Kim, Sunam Jeon, Moon Jip Park +1
The Hofstadter energy spectrum of twisted bilayer graphene is found to have recursive higher-order topological properties. We demonstrate that higher-order topological insulator (H…
Tunable bulk photovoltaic effect in strained -GeSe
Hong-Guk Min, Churlhi Lyi, Youngkuk Kim
Recently, Lee \textit{et. al.} [Nano Lett. \textbf{21}, 4305 (2021)] newly synthesized monochalcogenide GeSe in a polar phase, referred to as -phase. Motivated by this work, we…
Monolayer Kagome Metals AVSb
Sun-Woo Kim, Hanbit Oh, Eun-Gook Moon +1
Recently, layered kagome metals AVSb (A = K, Rb, and Cs) have emerged as a fertile platform for exploring frustrated geometry, correlations, and topology. Here, using first…
Two-dimensional weak-type topological insulators in inversion symmetric crystals
Sunam Jeon, Youngkuk Kim
The Su-Schrieffer-Heeger (SSH) chain is an one-dimensional lattice that comprises two dimerized sublattices. Recently, Zhu, Prodan, and Ahn (ZPA) proposed in [L. Zhu, E. Prodan, an…
Nonlinear optical Hall effect in Weyl semimetal WTe2
Young-Gwan Choi, Manh-Ha Doan, Youngkuk Kim +1
The ordinary Hall effect refers to generation of a transverse voltage upon exertion of an electric field in the presence of an out-of-plane magnetic field. While a linear Hall effe…
On-demand quantum spin Hall insulators controlled by two-dimensional ferroelectricity
Jiawei Huang, Xu Duan, Sunam Jeon +4
The coexistence of ferroelectric and topological orders in two-dimensional (2D) atomic crystals allows non-volatile and switchable quantum spin Hall states. Here we offer a general…
Higher-Order Topological Instanton Tunneling Oscillation
Moon Jip Park, Sunam Jeon, SungBin Lee +2
We propose a new type of instanton interference effect in two-dimensional higher-order topological insulators. The intercorner tunneling consists of the instanton and the anti-inst…
Higher-Order Topological Insulator in Twisted Bilayer Graphene
Moon Jip Park, Youngkuk Kim, Gil Young Cho +1
Higher-order topological insulators are newly proposed topological phases of matter, whose bulk topology manifests as localized modes at two- or higher-dimensional lower boundaries…
Stiefel-Whitney classes and topological phases in band theory
Junyeong Ahn, Sungjoon Park, Dongwook Kim +2
In this article, we review the recent progress in the study of topological phases in systems with space-time inversion symmetry . is an anti-unitary…
Dual topological nodal line and nonsymmorphic Dirac semimetal in three dimensions
Yun-Tak Oh, Hong-Guk Min, Youngkuk Kim
Previously known three-dimensional Dirac semimetals (DSs) occur in two types -- topological DSs and nonsymmorphic DSs. Here we present a novel three-dimensional DS that exhibits bo…
Topological Semimetals from first-principles
Heng Gao, Jörn W. F. Venderbos, Youngkuk Kim +1
We review recent theoretical progress in the understanding and prediction of novel topological semimetals. Topological semimetals define a class of gapless electronic phases exhibi…
Ferromagnetic nodal-line metal in monolayer {\em h}-InC
Sunam Jeon, Yun-Tak Oh, Youngkuk Kim
Based on first-principles calculations, we predict a new two-dimensional ferromagnetic material that exhibits exotic Fermi surface topology. We show that monolayer hexagonal indium…
Type-II Dirac line node in strained Na3N
Dongwook Kim, Seongjin Ahn, Jong Hyun Jung +4
Dirac line node (DLN) semimetals are a class of topological semimetals that feature band-crossing lines in momentum space. We study the type-I and type-II classification of DLN sem…
Band Topology and Linking Structure of Nodal Line Semimetals with Z2 Monopole Charges
Junyeong Ahn, Dongwook Kim, Youngkuk Kim +1
We study the band topology and the associated linking structure of topological semimetals with nodal lines carrying monopole charges, which can be realized in three-dimensi…
Double Dirac Semimetals in Three Dimensions
Benjamin J. Wieder, Youngkuk Kim, A. M. Rappe +1
We study a class of Dirac semimetals that feature an eightfold-degenerate double Dirac point. We show that 7 of the 230 space groups can host such Dirac points and argue that they…
Substantial optical dielectric enhancement by volume compression in LiAsSe
Fan Zheng, John A. Brehm, Steve M. Young +2
Based on first-principles calculations, we predict a substantial increase in the optical dielectric function of LiAsSe under pressure. We find that the optical dielectric const…
Strain Induced Ferroelectric Topological Insulator
Shi Liu, Youngkuk Kim, Liang Z. Tan +1
The simultaneous presence of seemingly incompatible properties of solids often provides a unique opportunity to address questions of fundamental and practical importance. The coexi…
Dirac Line Nodes in Inversion Symmetric Crystals
Youngkuk Kim, Benjamin J. Wieder, C. L. Kane +1
We propose and characterize a new class of topological semimetals with a vanishing spin--orbit interaction. The proposed topological semimetals are characterized by…
Layered Topological Crystalline Insulators
Youngkuk Kim, C. L. Kane, E. J. Mele +1
Topological crystalline insulators (TCIs) are insulating materials whose topological property relies on generic crystalline symmetries. Based on first-principles calculations, we s…