Pohang University of Science and Technology · Physics and Astronomy
Professor Ki-Seok Kim's research lab specializes in quantum materials and strongly correlated electron systems, with a focus on emergent quantum phenomena at oxide and van der Waals heterointerfaces. The lab investigates topological quantum states, including Weyl semimetals and heavy fermion systems, exploring their transport properties near quantum critical points. Using advanced spectroscopic techniques like angle-resolved photoemission spectroscopy (ARPES) and theoretical modeling, the group uncovers the interplay between electronic reconstruction, Fermi surface topology, and non-Fermi liquid behavior.
Figures are computed from collected data and may differ slightly.
Emergent phenomena driven by electronic reconstructions in oxide heterostructures have been intensively discussed. However, the role of these phenomena in shaping the electronic properties in van der Waals heterointerfaces has hitherto not been established. By reducing the material thickness and forming a heterointerface, we find two types of charge-ordering transitions in monolayer VSe<sub>2</sub> on graphene substrates. Angle-resolved photoemission spectroscopy (ARPES) uncovers that Fermi-surf
The backstepping control method provides useful control logic, especially for a cascaded system. Because spacecraft dynamics and kinematics form a cascaded system, the spacecraft slew maneuver problem can be solved using the backstepping control method. However, the simple linear backstepping controller may result in poor design: sluggish motion, trivial nonlinear term cancellation, and excessive control input. To overcome these defects, an effective backstepping control method using a nonlinear
Weyl metal is regarded as a platform toward interacting topological states of matter, where its topological structure gives rise to anomalous transport phenomena, referred to as chiral magnetic effect and ``negative'' magnetoresistivity, the origin of which is chiral anomaly. Recently, the negative magnetoresistivity has been observed with the signature of weak antilocalization at $x=3--4%$ in ${\mathrm{Bi}}_{1\ensuremath{-}x}$${\mathrm{Sb}}_{x}$, where a magnetic field is applied in parallel wi
A reconfigurable flight control system provides better survivability through the automatic reconfiguration of control system when faults occur during flight. The adaptive control method has been effectively applied to the reconfigurable flight control system design. However, reconfigurable flight control systems based on the indirect adaptive control method require persistent input excitation and smooth input-output data. To deal with the persistent input excitation problem and to obtain smooth
We study the electrical and thermal transport near the heavy-fermion quantum critical point, identified with the breakdown of the Kondo effect. We show that the electrical conductivity comes mainly from conduction electrons while the thermal conductivity is given by both conduction electrons and localized fermions (spinons), scattered with hybridization fluctuations of dynamical exponent z = 3. As a result, we reveal that not only electrical but also thermal resistivity displays quasilinear temp
We present a series of arguments showing that the Seebeck coefficient can be used as a decisive experiment to characterize the nature of the quantum-critical point (QCP) in heavy fermion compounds. Being reactive almost exclusively to the presence of delocalized entropic carriers, the Seebeck coefficient shows a drastic collapse at the Kondo breakdown QCP, as the reconstruction of the Fermi surface takes place. In contrast, around a spin-density-wave QCP, the Seebeck coefficient is broadly symme
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