Research Activities

[Keehoon Kang, Prof. Takhee Lee] Layer-by-Layer Structural Identification of 2D Ruddlesden–Popper Hy... Jan 28, 2021 l Hit 3165

Application of two-dimensional (2D) organic–inorganic hybrid halide perovskites in optoelectronic devices requires a detailed understanding of the local structural features including the Pb–I bonding in the 2D layers and the organic–inorganic interaction between the organic spacer molecules and the pe...

Momentum-dependent magnon lifetime in the metallic non-collinear triangular antiferromagnet CrB2 Jul 9, 2020 l Hit 2569

Noncollinear magnetic order arises for various reasons in several magnetic systems and exhibits interesting spin dynamics. Despite its ubiquitous presence, little is known of how magnons, otherwise stable quasiparticles, decay in these systems, particularly in metallic magnets. Using inelastic neutron scattering, we ex...

[Dr. K.H.Kim, H. Kang, Prof. Y.W.Park] Ultrafast Transient Spectroscopy of Trans-Polyacetylene in th... Jan 28, 2020 l Hit 2551

Trans-polyacetylene [t−(CH)x ] possesses twofold ground state degeneracy. Using the Su-Schrieffer-Heeger Hamiltonian, scientists predicted charged solitons to be the primary photoexcitations in t−(CH)x ; this prediction, however, has led to sharp debate. To resolve this saga, we use subpicosecond transient ...

[Quantum Gas Lab] Kibble-Zurek universality in a strongly interacting Fermi superfluid (Nature Physi... Sep 18, 2019 l Hit 2457

Kibble-Zurek universality in a strongly interacting Fermi superfluid The Kibble-Zurek mechanism describes the spontaneous formation of topological defects in a system crossing a continuous phase transition. Its central premise is the notion of universality, which states that the characteristic scaling exponent describi...

[Jinsu Pak, Dr. Seungjun Chung, and Prof. Takhee Lee]  Intrinsic Optoelectronic Characteristics of M... Aug 2, 2019 l Hit 3780

In the past decade, intensive studies on monolayer MoS2-based phototransistors have been carried out to achieve further enhanced optoelectronic characteristics. However, the intrinsic optoelectronic characteristics of monolayer MoS2 have still not been explored until now because of unintended interferences, such as mul...

[Dr. Myungjae Lee, Prof. Heonsu Jeon] The paper “Taming of random lasers” chosen for the cover page ... Jul 2, 2019 l Hit 2285

The research paper “Taming of random lasers” by Prof. Heonsu Jeon’s group, published online in the last April, now appears in the cover of the July 2019 issue of Nature Photonics, along with the following introductory remarks: Random lasers are notorious for their unpredictability and uncontrollabilit...

[Kunook Chung, Keundong Lee, ,Prof. Gyu-Chul] GaN microstructure light-emitting diodes directly fabr... May 1, 2019 l Hit 2291

We report on the selective-area growth of GaN microstructures on tungsten (W)-metal electrodes using a micro-patterned graphene intermediate layer between GaN and W, and demonstrate their use as light-emitting diodes (LEDs). Prior to the GaN growths, the cm-scale graphene layer was transferred on W and then further pat...

[C. Han/Prof. H. Jeon] Lasing at topological edge states in a photonic crystal L3 nanocavity dimer a... May 1, 2019 l Hit 2747

Topological photonics have provided new insights for the manipulation of light. Analogous to electrons in topological insulators, photons travelling through the surface of a topological photonic structure or the interface of two photonic structures with different topological phases are free from backscattering caused b...

[Dr. Keehoon Kang / Heebeom Ahn / Prof. Takhee Lee] High-Performance Solution-Processed Organo-Halid... Apr 16, 2019 l Hit 2131

Resistive random access memories can potentially open a niche area in memory technology applications by combining the advantages of a long endurance of dynamic random-access memory and a long retention time of flash memories. Recently, resistive memory devices based on organo-halide perovskite materials have demonstrat...

[Quantum Gas Lab.] Observation of Wall-Vortex Composite Defects in a Spinor Bose-Einstein Condensate... Mar 11, 2019 l Hit 2250

We report the observation of spin domain walls bounded by half-quantum vortices (HQVs) in a spin-1 Bose-Einstein condensate with antiferromagnetic interactions. A spinor condensate is initially prepared in the easy-plane polar phase, and then, suddenly quenched into the easy-axis polar phase. Domain walls are created v...