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Your search keyword '"Kang, M.‐G."' showing total 142 results
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142 results on '"Kang, M.‐G."'

3. Tuning the Fano Resonance with an Intruder Continuum

Author

Fransson, J., Kang, M. -G., Yoon, Y., Xiao, S., Ochiai, Y., Reno, J. L., Aoki, N., and Bird, J. P.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Quantum Physics
Abstract

Through a combination of experiment and theory we establish the possibility of achieving strong tuning of Fano resonances (FRs), by allowing their usual two-path geometry to interfere with an additional, 'intruder', continuum. As the coupling strength to this intruder is varied, we predict strong modulations of the resonance line shape that, in principle at least, may exceed the amplitude of the original FR itself. For a proof-of-concept demonstration of this phenomenon, we construct a nanoscale interferometer from nonlocally coupled quantum point contacts and utilize the unique features of their density of states to realize the intruder. External control of the intruder coupling is enabled by means of an applied magnetic field, in the presence of which we demonstrate the predicted distortions of the FR. This general scheme for resonant control should be broadly applicable to a variety of wave-based systems, opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications., Comment: 19 pages, 4 figures

Published
2014
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4. Insulator, semiclassical oscillations and quantum Hall liquids at low magnetic fields

Author

Lo, Shun-Tsung, Wang, Yi-Ting, Bohra, G, Comfort, E, Lin, T-Y, Kang, M-G, Strasser, G, Bird, J P, Huang, C F, Lin, Li-Hung, Chen, J C, and Liang, C-T

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

Magneto-transport measurements are performed on two-dimensional GaAs electron systems to probe the quantum Hall (QH) effect at low magnetic fields. Oscillations following the Shubnikov-de Haas (SdH) formula are observed in the transition from the insulator to QH liquid when the observed almost temperature-independent Hall slope indicates insignificant interaction correction. Our study shows that the existence of SdH oscillations in such a transition can be understood based on the non-interacting model., Comment: 17 pages

Published
2012
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5. Coupling Remote States through the Continuum: Multi-State Fano Resonances

Author

Yoon, Y., Kang, M. -G., Morimoto, T., Kida, M., Aoki, N., Reno, J. L., Ochiai, Y., Mourokh, L., and Bird, J. P.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We demonstrate a fully-tunable multi-state Fano system in which remotely-implemented quantum states interfere with each other through their coupling to a mutual continuum. On tuning these resonances near coincidence a robust avoided crossing is observed, with a distinctive character that confirms the continuum as the source of the coupling. While the continuum often serves as a source of decoherence, our work therefore shows how its presence can instead also be essential to mediate the interaction of quantum states, a result that could allow new approaches to engineer the collective states of nanostructures.

Published
2009

7. Detector Backaction on the Self-Consistent Bound State in Quantum Point Contacts

Author

Yoon, Y., Kang, M. -G., Morimoto, T., Mourokh, L., Aoki, N., Reno, J. L., Bird, J. P., and Ochiai, Y.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Bound-state (BS) formation in quantum point contacts (QPCs) may offer a convenient way to localize and probe single spins. In this letter, we investigate how such BSs are affected by monitoring them with a second QPC, which is coupled to the BS via wavefunction overlap. We show that this coupling leads to a unique detector backaction, in which the BS is weakened by increasing its proximity to the detector. We also show, however, that this interaction between the QPCs can be regulated at will, by using an additional gate to control their wavefunction overlap.

Published
2008
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25. Comparison of Strain in GaN-Based Blue Light-Emitting Diode Grown on Silicon(111) and Sapphire Substrates

Author

Jeon, K. S., primary, Sung, J. H., additional, Lee, M. W., additional, Song, H. Y., additional, Lee, E. A., additional, Kim, S. O., additional, Choi, H. J., additional, Shin, H. Y., additional, Park, W. H., additional, Jang, Y. I., additional, Kang, M. G., additional, Choi, Y. H., additional, Lee, J. S., additional, Ko, D. H., additional, and Ryu, H. Y., additional

Published
2015
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28. Talking through the continuum : New manifestations of Fano-resonance phenomenology realized with mesoscopic nanostructures

Author

Xiao, S., Xiang, S., Yoon, Y., Kang, M. -G, Kida, M., Aoki, N., Reno, J. L., Ochiai, Y., Mourokh, L., Fransson, Jonas, Bird, J. P., Xiao, S., Xiang, S., Yoon, Y., Kang, M. -G, Kida, M., Aoki, N., Reno, J. L., Ochiai, Y., Mourokh, L., Fransson, Jonas, and Bird, J. P.

Abstract

The focus of this review is recent work in which we have demonstrated a highly-flexible approach to the study of Fano-resonance phenomena, by making use of the mesoscopic devices known as quantum point contacts (QPCs). Utilizing the ability of these structures to function as an on-demand quantum state, we demonstrate a highly-flexible system for the investigation of Fano resonances. Our approach involves making measurements of non-locally coupled pairs of QPCs, one of which is used to form the discrete state needed for the Fano resonance, while the other serves as a detector whose conductance is sensitive to the energy of this state. As a demonstration of the flexibility of this approach, we show how it can be used to implement a multi-state Fano resonance, in which two discrete states undergo a robust interaction that is achieved by coupling them to each other through a common continuum.

Published
2013
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30. Coupling Quantum States through a Continuum : A Mesoscopic Multistate Fano Resonance

Author

Yoon, Y., Kang, M. -G, Morimoto, T., Kida, M., Aoki, N., Reno, J. L., Ochiai, Y., Mourokh, L., Fransson, Jonas, Bird, J. P., Yoon, Y., Kang, M. -G, Morimoto, T., Kida, M., Aoki, N., Reno, J. L., Ochiai, Y., Mourokh, L., Fransson, Jonas, and Bird, J. P.

Abstract

We demonstrate a fully tunable realization of a multistate Fano resonance, in which a pair of remote quantum states experience an effective coupling due to their mutual overlap with a continuum. Our mesoscopic implementation of this system exploits the ability of the semiconductor nanostructures known as quantum point contacts (QPCs) to serve, in the low-density limit close to pinch-off, as an on-demand localized state. By coupling the states formed on two separate QPCs, through a two-dimensional electron gas that serves as a continuum, we observe a robust effective interaction between the QPCs. To explain this result, we develop a theoretical formulation, based on the ideas of the Schrieffer-Wolff transformation, which is able to reproduce our key experimental findings. According to this model, the robust character of the interaction between the two remote states arises from the fact that the interaction is essentially mediated by a large number of degenerate continuum states. While the continuum is often viewed as a source of decoherence, our experiment therefore instead suggests the possibility of using this medium to support the interaction of quantum states, a result that may allow new approaches to coherently couple nanostructures in extended geometries.

Published
2012
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