News

[Kok Chuan Tan, Seongjeon Choi, and Hyunseok Jeong] Negativity of Quasiprobability Distributions as ... Mar 26, 2020 l Hit 1606

We demonstrate that the negative volume of any s-parametrized quasiprobability, including the Glauber-Sudashan P-function, can be consistently defined and forms a continuous hierarchy of nonclassicality measures that are linear optical monotones. These measures belong to an operational resource theory of nonclassicalit...

[Sungjoon Park,Prof. Bohm-Jung Yang] Thermal Hall Effect, Spin Nernst Effect, and Spin Density Induc... Mar 13, 2020 l Hit 1825

We theoretically study the intrinsic thermal Hall and spin Nernst effect in collinear ferrimagnets on a honeycomb lattice with broken inversion symmetry. The broken inversion symmetry allows in-plane Dzyaloshinskii−Moriya interaction between the nearest neighbors, which does not affect the linear spin wave theory...

[KPS Award Winner] Junyeong Ahn (Ph.D. Candidate) received the Young Physicist Prize! Oct 29, 2019 l Hit 2330

Junyeong Ahn, a Ph.D Candidate at Prof. Bohm-Jung Yang's group, won the Young Physicist Prize at the KPS autumm meeting held at Gwangju, Kim Dae Joong convention center for Oct.23-25, 2019. The Prize is awarded for Junyeong's outstanding achievement about the band topology of wave functions in space-time inversi...

[Quantum Gas Lab] Kibble-Zurek universality in a strongly interacting Fermi superfluid (Nature Physi... Sep 18, 2019 l Hit 2418

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 3744

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 2249

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...

[Changhee Lee, Prof. Hongki Min] Emergent Anisotropic Non-Fermi Liquid at a Topological Phase Transi... May 15, 2019 l Hit 1176

Understanding correlation effects in topological phases and their transitions is a cutting-edge area of research in recent condensed matter physics. We study topological quantum phase transitions (TQPTs) between double-Weyl semimetals (DWSMs) and insulators, and argue that a novel class of quantum criticality appears a...

[Kunook Chung, Keundong Lee, ,Prof. Gyu-Chul] GaN microstructure light-emitting diodes directly fabr... May 1, 2019 l Hit 2251

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 2701

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...

[Junyeong Ahn/Sungjoon Park, Prof. Bohm-Jung Yang] Failure of Nielsen-Ninomiya Theorem and Fragile T... Apr 24, 2019 l Hit 1185

We show that the Wannier obstruction and the fragile topology of the nearly flat bands in twisted bilayer graphene at magic angle are manifestations of the nontrivial topology of two-dimensional real wave functions characterized by the Euler class. To prove this, we examine the generic band topology of two dimensional ...