268 citations · 1.6k across the 22 of their papers we have counts for
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Quantum Oscillation Signatures of Monopole Charge in Nodal-Ring Semimetals
Aravind Karthigeyan, Yoonseok Hwang, Bohm-Jung Yang +1
Topological semimetals host band nodes characterized by quantized invariants that can appear in bulk responses, yet some invariants remain hidden from standard probes. In particula…
Topological Enhancement of Nonlinear Transports in Unconventional Point-Node Semimetals
Junyeong Ahn
The topological singularity of the Bloch states close to the Fermi level significantly enhances nonlinear electric responses in topological semimetals. Here, we systematically char…
Axion optical induction of antiferromagnetic order
Jian-Xiang Qiu, Christian Tzschaschel, Junyeong Ahn +25
Using circularly-polarized light to control quantum matter is a highly intriguing topic in physics, chemistry and biology. Previous studies have demonstrated helicity-dependent opt…
Topological Circular Dichroism in Chiral Multifold Semimetals
Junyeong Ahn, Barun Ghosh
Uncovering the physical contents of the nontrivial topology of quantum states is a critical problem in condensed matter physics. Here, we study the topological circular dichroism i…
Theory of optical axion electrodynamics and application to the Kerr effect in topological antiferromagnets
Junyeong Ahn, Su-Yang Xu, Ashvin Vishwanath
Emergent axion electrodynamics in magneto-electric media is expected to provide novel ways to detect and control material properties with electromagnetic fields. However, despite b…
Low-frequency divergence and quantum geometry of the bulk photovoltaic effect in topological semimetals
Junyeong Ahn, Guang-Yu Guo, Naoto Nagaosa
We study the low-frequency properties of the bulk photovoltaic effect in topological semimetals. The bulk photovoltaic effect is a nonlinear optical effect that generates DC photoc…
Unconventional Majorana fermions on the surface of topological superconductors protected by rotational symmetry
Junyeong Ahn, Bohm-Jung Yang
Topological superconductors are exotic gapped phases of matter hosting Majorana mid-gap states on their boundary. In conventional topological superconductors, Majorana in-gap state…
Topological Correspondence between Hermitian and Non-Hermitian Systems: Anomalous Dynamics
Jong Yeon Lee, Junyeong Ahn, Hengyun Zhou +1
The hallmark of symmetry-protected topological (SPT) phases is the existence of anomalous boundary states, which can only be realized with the corresponding bulk system. In this wo…
Higher-Order Topological Superconductivity of Spin-Polarized Fermions
Junyeong Ahn, Bohm-Jung Yang
We study the superconductivity of spin-polarized electrons in centrosymmetric ferromagnetic metals. Due to the spin-polarization and the Fermi statistics of electrons, the supercon…
Fragile Topology Protected by Inversion Symmetry: Diagnosis, Bulk-Boundary Correspondence, and Wilson Loop
Yoonseok Hwang, Junyeong Ahn, Bohm-Jung Yang
We study the bulk and boundary properties of fragile topological insulators (TIs) protected by inversion symmetry, mostly focusing on the class A of the Altland-Zirnbauer classific…
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…
Symmetry representation approach to topological invariants in -symmetric systems
Junyeong Ahn, Bohm-Jung Yang
We study the homotopy classification of symmetry representations to describe the bulk topological invariants protected by the combined operation of a two-fold rotation and…
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…
Unconventional topological phase transition in two-dimensional systems with space-time inversion symmetry
Junyeong Ahn, Bohm-Jung Yang
We study a topological phase transition between a normal insulator and a quantum spin Hall insulator in two-dimensional (2D) systems with time-reversal and two-fold rotation symmet…