Hyung Kook Choi

Jeonbuk National University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

V. Umansky

Weizmann Institute of Science

Yunchul Chung

Pusan National University

D. Mahalu

Weizmann Institute of Science

Chanuk Yang

Jeonbuk National University

Seung‐Hyun Chun

Sejong University

Dongsung T. Park

Korea Advanced Institute of Science and Technology

Kee Hoon Kim

Seoul National University

Z. G. Khim

Seoul National University

Yoon Seok Oh

Ulsan National Institute of Science and Technology

Uh Jin Kim

Chonnam National University

Cooperative Institutions

Seoul National University

Korea Advanced Institute of Science and Technology

Government of the Republic of Korea

Pusan National University

Jeonbuk National University

Weizmann Institute of Science

Korea Research Institute of Standards and Science

Korea Institute of Science and Technology

Yonsei University

University of Florida

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Manipulation of valley isospins in strained graphene for valleytronics

Carbon (2019)

Nojoon Myoung Hyung Kook Choi Hee Chul Park

Valleytronics

Strain engineering

Strain (injury)

10.1016/j.carbon.2019.10.040

Cite

Citations (21)

Attractive Coulomb interactions in a triple quantum dot

Physical review. B./Physical review. B (2018)

Changki Hong Gwangsu Yoo Jin‐Hong Park Min-Kyun Cho Yunchul Chung

This work demonstrates that electron pairing can be achieved purely by the Coulomb interactions in a triple quantum dot. Such a pairing mechanism is different from that of a Cooper pair. The electron pairing in two dots of the triple dot is mediated by the other (third) dot, when the third dot strongly couples with the two via Coulomb repulsion. By measuring electron conductance through each individual dot, the authors find the degeneracy for the pairing, the condition for the degeneracy, and nontrivial transport behavior by the pairing. These findings may be exploited to design quantum devices with nontrivial electron correlations and functionalities.

Degeneracy (biology)

Electron pair

Coulomb blockade

10.1103/physrevb.97.241115

Cite

Citations (16)

Nanomachining-enabled strain manipulation of magnetic anisotropy in the free-standing GaMnAs nanostructures

Scientific Reports (2019)

Chanuk Yang Jae-Hyun Lee Jong‐Gul Yoon Hyung Kook Choi Seondo Park

Abstract Strain perturbs atomic ordering in solids, with far-reaching consequences from an increased carrier mobility to localization in Si, stabilization of electric dipoles and nanomechanical transistor action in oxides, to the manipulation of spins without applying magnetic fields in n-GaAs. In GaMnAs, a carrier-mediated ferromagnetic semiconductor, relativistic spin-orbit interactions – highly strain-dependent magnetic interactions – play a crucial role in determining the magnetic anisotropy (MA) and anisotropic magnetoresistance (AMR). Strain modifies the MA and AMR in a nanomachined GaMnAs structure as measured by the anomalous Hall effect (AHE) and the planar Hall effect (PHE). Here, we report an MA modification by strain relaxation in an isolated GaMnAs Hall bar structure and by applying a range of local strains via fabricating asymmetrically mechanically buckled GaMnAs micro-Hall bar structures. In the AHE and PHE measurements, we observe a reduction in the in-plane MA and an enhancement in the out-of-plane MA as the compressive strain due to the lattice mismatch relaxes in the suspended structure. The functionality of such mechanical manipulation, as well as the two-level mechanical state and the corresponding AHE responses, is demonstrated by a fully scalable binary mechanical memory element in a GaMnAs single Hall cross structure.

Strain engineering

Electron Mobility

10.1038/s41598-019-50115-1

Cite

Citations (3)

Robust electron pairing in the integer quantum hall effect regime

Nature Communications (2015)

Hyung Kook Choi Itamar Sivan Amir Lafont Rosenblatt Moty Heiblum V. Umansky

Electron pairing is a rare phenomenon appearing only in a few unique physical systems; for example, superconductors and Kondo-correlated quantum dots. Here, we report on an unexpected electron pairing in the integer quantum Hall effect regime. The pairing takes place within an interfering edge channel in an electronic Fabry-Perot interferometer at a wide range of bulk filling factors, between 2 and 5. We report on three main observations: high-visibility Aharonov-Bohm conductance oscillations with magnetic flux periodicity equal to half the magnetic flux quantum; an interfering quasiparticle charge equal to twice the elementary electron charge as revealed by quantum shot noise measurements, and full dephasing of the pairs' interference by induced dephasing of the adjacent inner edge channel-a manifestation of inter-channel entanglement. Although this pairing phenomenon clearly results from inter-channel interaction, the exact mechanism that leads to electron-electron attraction within a single edge channel is not clear. We believe that substantial efforts are needed in order to clarify these intriguing and unexpected findings.

Dephasing

Electron pair

Aharonov–Bohm effect

10.1038/ncomms8435

Cite

Citations (47)

Non-monotonic dependence of the anomalous Hall coefficient scaling parameter in annealed Ga1−xMnxAs epifilms

Journal of Magnetism and Magnetic Materials (2006)

Hyung Kook Choi W.O. Lee Yoon Seok Oh Kee Hoon Kim Y.D. Park

Magnetic semiconductor

10.1016/j.jmmm.2006.10.935

Cite

Citations (0)

Interplay between Carrier and Impurity Concentrations in AnnealedGa1−xMnxAs: Intrinsic Anomalous Hall Effect

Physical Review Letters (2007)

Seung‐Hyun Chun Youn Sang Kim Hyung Kook Choi I. T. Jeong W. O. Lee

Investigating the scaling behavior of annealed Ga$_{1-x}$Mn$_{x}$As anomalous Hall coefficients, we note a universal crossover regime where the scaling behavior changes from quadratic to linear, attributed to the anomalous Hall Effect intrinsic and extrinsic origins, respectively. Furthermore, measured anomalous Hall conductivities when properly scaled by carrier concentration remain constant, equal to theoretically predicated values, spanning nearly a decade in conductivity as well as over 100 K in T$_{C}$. Both the qualitative and quantitative agreement confirms the validity of new equations of motion including the Berry phase contributions as well as tunablility of the intrinsic anomalous Hall Effect.

Scaling law

10.1103/physrevlett.98.026601

Cite

Citations (51)

Strain manipulation of anomalous Hall response in GaMnAs micromechanical buckled Hall beam structure

Bulletin of the American Physical Society (2011)

Chanuk Yang Hyung Kook Choi Tai-hoon Kim Yun Daniel Park

Strain (injury)

Source

Cite

Citations (0)

A label-free size-based micro coulter counter system for circulating rare tumor cells

17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 (2013)

Hyung Kook Choi C. S. Jeon H. K. Kim Taek Dong Chung Hee Chan Kim

In clinical and biological fields, circulating tumor cells (CTCs) have been becoming an important topic because of their critical role in cancer metastasis. Many researchers reported that the number of CTCs is highly-related with the survival rates of cancer patients. Hence, we described a label-free size-based micro coulter counter system to count CTCs in human blood. We examined OVCAR-3 cells spiked blood samples and obtained decent results with 88% efficiency. Furthermore, we tested breast cancer patient samples and detected CTCs in 24 patient samples. Therefore, the developed system shows a facile way to count CTCs regardless of biomarkers.

Coulter counter

Circulating tumor cell

Source

Cite

Citations (0)

Transport across a pinned domain wall across a GaMnAs constriction: from AMR to spin-dependent tunneling.

Bulletin of the American Physical Society (2009)

Sung Un Cho Hyung Kook Choi Fabio C.S. DaSilva Teresa Osminer David P. Pappas

Domain wall (magnetism)

Constriction

Source

Cite

Citations (0)

One-Lead Single-Electron Source with Charging Energy

Nano Letters (2022)

Sung Un Cho Wanki Park Bum-Kyu Kim Minky Seo Dongsung T. Park

Single-electron sources, formed by a quantum dot (QD), are key elements for realizing electron analogue of quantum optics. We develop a new type of single-electron source with functionalities that are absent in existing sources. This source couples with only one lead. By an AC rf drive, it successively emits holes and electrons cotraveling in the lead, as in the mesoscopic capacitor. Thanks to the considerable charging energy of the QD, however, emitted electrons have energy levels a few tens of millielectronvolts above the Fermi level, so that emitted holes and electrons are split by a potential barrier on demand, resulting in a rectified quantized current. The resulting pump map exhibits quantized triangular islands, in good agreement with our theory. We also demonstrate that the source can be operated with another tunable-barrier single-electron source in a series double QD geometry, showing parallel electron pumping by a common gate driving.

Mesoscopic physics

Fermi energy

10.1021/acs.nanolett.2c02893

Cite

Citations (2)