Myoung-Hwan Kim, Ph.D.
Department of Physics and Astronomy
Room Number: 111 Science Building
Ph.D. Physics, The State University of New York at Buffalo (2010)
M.S. Physics, POSTECH, Korea (1999)
B.S. Physics, Hanyang University, Korea (1997)
Research Group Webpage
Our infrared laboratory utilize various infrared spectroscopy and polarimetry technique to investigate quantum
materials and novel nanostructures. Our main research focus on studying anomalous
Hall behavior in quantum materials of fundamental interest and developing novel surface
polaritonic nano-device and rare-earth spin quantum sensor for infrared applications.
Mid-Far Infrared Anomalous Hall Effect
Magnetic Weyl Semimetals. Topological materials are new type of quantum materials which phases of matter are
classified by surface states produced by the topology of the bulk band structure.
Among them, topological Weyl semimetals have received a lot of attention because of
quantum anomalies such as a topological Fermi arc and chiral anomaly from Weyl fermions,
which allow quantum control of topologies electrically and optically. Recent material
survey extends to rare-earth based magnetic non-centrosymmetric Weyl semimetals showing
a rich topological tunability of Weyl fermions at the low-energy band structures below
100 meV. The simplest investigation of Weyl fermions is to measure anomalous Hall
conductivity. We are interested in probing and understanding low-energy infrared magneto-transport
fingerprints of Weyl fermions in magnetic Weyl semimetals under broken time-reversal
symmetry. Hall measurement at finite frequencies near dc to infrared has rarely been
considered because the mid-far infrared magneto-polarimetry measurement has still
been challenged so far. Our group addresses the challenge by developing mid-far infrared
Hall spectrometer at Texas Tech University which aims to access the under-explored
low-energy infrared anomalous Hall conductivity close to dc.
Tailoring Evanescent Light on Surface
Surface Phonon Polaritonic Metasurfaces. Gradient optical metasurfaces have been used to demonstrate a wavefront control of
light in free space and in optical waveguides by imposing spatially varying optical
responses to the light. However, the control of light localized and propagating on
surface has been challenging because the surface waves scatter intensively to the
metallic metasurfaces causing the optical loss. Can we find new metasurfaces platform
to tailor the surface waves of light? Our group addresses the challenge by understanding
fundamentally the near-field interaction between surface waves of light and surface
charge oscillations confined in gradient metasurfaces. The research project will deal
with the technologically important long-wavelength infrareds and result in producing
active flat optical components, perfect infrared absorbers, narrow-band thermal emitters
and detectors, optical isolators, and phase modulators in mid and far infrared.
Rare-earth Spin Qubit. Rare-earth spin qubits are a promising quantum system because of narrow energy level
transition, as well as long optical and spin coherence lifetimes at visible and near
infrared. Numerous materials host rare-earth spin qubits including yttrium orthosilicate,
yttrium aluminum oxide, and lithium niobate, all of which essentially resist decoherence
of the quantum state caused by hosting material interactions. The hosting material
should be CMOS-compatible to integrate with classical photonic circuits. CMOS-compatible
materials are easily structured in nanoscale to create waveguides or optical cavities
and enhance light-matter interaction for a long photon lifetime. However, current
rare-earth doped systems are far from CMOS-compatible. We are interested in developing
on-chip quantum sensing devices based on rare-earth spin qubits in CMOS-compatible
and active material platform.
C. Wang, Z. Li, M.-H. Kim, X. Xiong, X.-F. Ren, G.-C. Guo, N. Yu, and M. Loncar, "Metasurface-assisted phase-matching-free second harmonic generation in lithium niobate waveguides" Nature Communications Vol. 8, 2098 (2017)
Z. Li, M.-H. Kim, C. Wang, Z. Han, S. Shrestha, A. C. Overvig, M. Lu, A. Stein, A. M. Agarwal, M. Loncar, and N. Yu, "Controlling propagation and coupling of waveguide modes using phase-gradient metasurfaces," Nature Nanotechnology Vol. 12, 675 - 68 (2017).
M.-H. Kim, J. Yan, R. J. Suess, T. E. Murphy, M. S. Fuhrer, and H. D. Drew, "Photothermal response in dual-gated bilayer graphene," Phys. Rev. Lett. Vol. 110, 247402 (2013).
J. Yan, M.-H. Kim, J. A. Elle, A. B. Sushkov, G. S. Jenkins, H. M. Milchberg, M. S. Fuhrer, and H. D. Drew, "Dual-gated bilayer graphene hot electron bolometer," Nature Nanotechnology Vol. 7, 472 – 478 (2012).
M.-H. Kim, G. Acbas, M.-H. Yang, I. Ohkubo, H. Christen, D. Mandrus, M. A. Scarpulla, O. D. Dubon, Z. Schlesinger, P. Khalifah, and J. Cerne, "Determination of the infrared complex magnetoconductivity tensor in itinerant ferromagnets from Faraday and Kerr measurements," Phys. Rev. B Vol. 75, 214416 (2007).