Jae Hyuck Lee
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Jae Hyuck Lee has a total of 51 co-authors. Here are the top co-authors by number of shared publications:
- Changyoung Kim
Seoul National University
4 shared publications Changyoung Kim
Seoul National University
2 shared publications- Dirk Wulferding
Department of Physics and Astronomy Sejong University Seoul Republic of Korea
2 shared publications - Dongjoon Song
The University of British Columbia
2 shared publications - Heung-Sik Kim
Kangwon National University
2 shared publications - Hyun Cheol Lee
Department of Physics Sogang University 04107 Seoul Republic of Korea
2 shared publications
Latest Publications
- 4 September 2026
- Published by American Physical Society (APS) in Physical Review B
- Vol. 114 (15) , 154405
Competing Ru magnetic orders in the spin-1 X Y pyrochlore Nd 2 Ru 2 O 7
Magnetic pyrochlore oxides exhibit various unconventional electronic phases and excitations due to geometric frustration. Recently, a collective magnetic excitation was reported in Raman spectroscopy on a pyrochlore ruthenate ${\mathrm{Nd}}_{2}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$. However, its origin remains unclear as the Ru magnetic ground state has been controversial due to sample quality and inconsistent experimental interpretations. Here, we performed neutron diffraction measurements on a high-quality polycrystalline sample with a nearly absent magnetic impurity phase. Magnetic susceptibility and neutron diffraction measurements reveal an intrinsic Ru magnetic transition at around 145.6 K, whereas a controversial magnetic anomaly at around 21 K is suppressed in our sample, indicating that the latter is dominantly from the magnetic impurity phase. Below 145.6 K, well-defined magnetic Bragg peaks from Ru moments were observed, implying well-formed spin-spin correlations. Magnetic refinements combined with magnetic space group analysis revealed competing Ru magnetic structures, supported by density functional theory calculations. Our results suggest that the collective Raman signal may arise from competing Ru magnetic orders. Order-by-disorder and energetic scenarios are discussed as selection mechanisms for the Ru magnetic ground state. This study provides crucial insights into the search for possible order-by-disorder and topological magnetic properties in a less-studied spin-1 pyrochlore.- 4 September 2026
- Published by American Physical Society (APS) in Physical Review B
- Vol. 114 (15) , 154405
Competing Ru magnetic orders in the spin-1 X Y pyrochlore Nd 2 Ru 2 O 7
Magnetic pyrochlore oxides exhibit various unconventional electronic phases and excitations due to geometric frustration. Recently, a collective magnetic excitation was reported in Raman spectroscopy on a pyrochlore ruthenate ${\mathrm{Nd}}_{2}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$. However, its origin remains unclear as the Ru magnetic ground state has been controversial due to sample quality and inconsistent experimental interpretations. Here, we performed neutron diffraction measurements on a high-quality polycrystalline sample with a nearly absent magnetic impurity phase. Magnetic susceptibility and neutron diffraction measurements reveal an intrinsic Ru magnetic transition at around 145.6 K, whereas a controversial magnetic anomaly at around 21 K is suppressed in our sample, indicating that the latter is dominantly from the magnetic impurity phase. Below 145.6 K, well-defined magnetic Bragg peaks from Ru moments were observed, implying well-formed spin-spin correlations. Magnetic refinements combined with magnetic space group analysis revealed competing Ru magnetic structures, supported by density functional theory calculations. Our results suggest that the collective Raman signal may arise from competing Ru magnetic orders. Order-by-disorder and energetic scenarios are discussed as selection mechanisms for the Ru magnetic ground state. This study provides crucial insights into the search for possible order-by-disorder and topological magnetic properties in a less-studied spin-1 pyrochlore.- 17 April 2026
- Published by Elsevier in Current Applied Physics
- Vol. 88, 29-35
Definitive Fermi-surface mapping of high-purity RuO2 via angle-dependent quantum oscillations
- 17 April 2026
- Published by Elsevier in Current Applied Physics
- Vol. 88, 29-35
Definitive Fermi-surface mapping of high-purity RuO2 via angle-dependent quantum oscillations
- Open Access
- 27 June 2025
- Published by American Association for the Advancement of Science (AAAS) in Science Advances
- Vol. 11 (26) , eadw7125
Anisotropic strain relaxation-induced directional ultrafast carrier dynamics in RuO 2 films
Ultrafast light-matter interactions inspire potential functionalities in picosecond optoelectronic applications. However, achieving directional carrier dynamics in metals remains challenging due to strong carrier scattering within a multiband environment, typically expected for isotropic carrier relaxation. In this study, we demonstrate epitaxial RuO 2 /TiO 2 (110) heterostructures grown by hybrid molecular beam epitaxy to engineer polarization selectivity of ultrafast light-matter interactions via anisotropic strain engineering. Combining spectroscopic ellipsometry, x-ray absorption spectroscopy, and optical pump-probe spectroscopy, we revealed the strong anisotropic transient optoelectronic response at an excitation energy of 1.58 eV in strain-engineered RuO 2 /TiO 2 (110) heterostructures along both in-plane [001] and [1 1 ¯ 0] crystallographic directions. Theoretical analysis identifies strain-induced modifications in band nesting as the underlying mechanism for enhanced anisotropic carrier relaxation observed at this excitation energy. These findings establish epitaxial strain engineering as a powerful tool for tuning anisotropic optoelectronic responses with near-infrared excitations in metallic systems, paving the way for next-generation polarization-sensitive ultrafast optoelectronic devices.
- 27 June 2025
- Published by American Association for the Advancement of Science (AAAS) in Science Advances
- Vol. 11 (26) , eadw7125
Open AccessAnisotropic strain relaxation-induced directional ultrafast carrier dynamics in RuO 2 films
Ultrafast light-matter interactions inspire potential functionalities in picosecond optoelectronic applications. However, achieving directional carrier dynamics in metals remains challenging due to strong carrier scattering within a multiband environment, typically expected for isotropic carrier relaxation. In this study, we demonstrate epitaxial RuO 2 /TiO 2 (110) heterostructures grown by hybrid molecular beam epitaxy to engineer polarization selectivity of ultrafast light-matter interactions via anisotropic strain engineering. Combining spectroscopic ellipsometry, x-ray absorption spectroscopy, and optical pump-probe spectroscopy, we revealed the strong anisotropic transient optoelectronic response at an excitation energy of 1.58 eV in strain-engineered RuO 2 /TiO 2 (110) heterostructures along both in-plane [001] and [1 1 ¯ 0] crystallographic directions. Theoretical analysis identifies strain-induced modifications in band nesting as the underlying mechanism for enhanced anisotropic carrier relaxation observed at this excitation energy. These findings establish epitaxial strain engineering as a powerful tool for tuning anisotropic optoelectronic responses with near-infrared excitations in metallic systems, paving the way for next-generation polarization-sensitive ultrafast optoelectronic devices.
- 30 August 2024
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 18 (37) , 25535-25541
Atomically Thin Two-Dimensional Kagome Flat Band on the Silicon Surface
In condensed matter physics, the Kagome lattice and its inherent flat bands have attracted considerable attention for their prediction and observation to host a variety of exotic physical phenomena. Despite extensive efforts to fabricate thin films of Kagome materials aimed at modulating flat bands through electrostatic gating or strain manipulation, progress has been limited. Here, we report the observation of a d-orbital hybridized Kagome-derived flat band in Ag/Si(111) as revealed by angle-resolved photoemission spectroscopy. Our findings indicate that silver atoms on a silicon substrate form an unconventional distorted breathing Kagome structure, where a delicate balance in the hopping parameters of the in-plane d-orbitals leads to destructive interference, resulting in double flat bands. The exact quantum destructive interference mechanism that forms the flat band is uncovered in a rigorous manner that has not been described before. These results illuminate the potential for integrating metal-semiconductor interfaces on semiconductor surfaces into Kagome physics, particularly in exploring the flat bands of ideal 2D Kagome systems.- 30 August 2024
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 18 (37) , 25535-25541
Atomically Thin Two-Dimensional Kagome Flat Band on the Silicon Surface
In condensed matter physics, the Kagome lattice and its inherent flat bands have attracted considerable attention for their prediction and observation to host a variety of exotic physical phenomena. Despite extensive efforts to fabricate thin films of Kagome materials aimed at modulating flat bands through electrostatic gating or strain manipulation, progress has been limited. Here, we report the observation of a d-orbital hybridized Kagome-derived flat band in Ag/Si(111) as revealed by angle-resolved photoemission spectroscopy. Our findings indicate that silver atoms on a silicon substrate form an unconventional distorted breathing Kagome structure, where a delicate balance in the hopping parameters of the in-plane d-orbitals leads to destructive interference, resulting in double flat bands. The exact quantum destructive interference mechanism that forms the flat band is uncovered in a rigorous manner that has not been described before. These results illuminate the potential for integrating metal-semiconductor interfaces on semiconductor surfaces into Kagome physics, particularly in exploring the flat bands of ideal 2D Kagome systems.- 31 August 2023
- Published by American Physical Society (APS) in Physical Review B
- Vol. 108 (5) , 054443
Linear scaling relationship of Néel temperature and dominant magnons in pyrochlore ruthenates
We present a systematic Raman spectroscopy study on a series of pyrochlore ruthenates, a system which is not yet clearly settled on its magnetic origin and structure. Apart from the Raman-active phonon modes, new peaks that appear in the energy range of 15–35 meV below the Néel temperature are assigned as one-magnon modes. The temperature evolution of one-magnon modes displays no significant thermal dependence in mode frequencies, while the intensities decrease monotonically. Remarkably, one magnons from all compounds show similar characteristics with a single dominant peak at lower energy and weaker side peaks at a couple of meV higher energy. Most importantly, we uncover a striking proportionality between the dominant magnon mode energies and the values. Our results suggest the Ru ions may have similar or the same magnetic phase in all pyrochlore ruthenates of our study. We have thus found an avenue for directly tuning the magnetic exchange interaction by the selection of the -site ion.- 31 August 2023
- Published by American Physical Society (APS) in Physical Review B
- Vol. 108 (5) , 054443
Linear scaling relationship of Néel temperature and dominant magnons in pyrochlore ruthenates
We present a systematic Raman spectroscopy study on a series of pyrochlore ruthenates, a system which is not yet clearly settled on its magnetic origin and structure. Apart from the Raman-active phonon modes, new peaks that appear in the energy range of 15–35 meV below the Néel temperature are assigned as one-magnon modes. The temperature evolution of one-magnon modes displays no significant thermal dependence in mode frequencies, while the intensities decrease monotonically. Remarkably, one magnons from all compounds show similar characteristics with a single dominant peak at lower energy and weaker side peaks at a couple of meV higher energy. Most importantly, we uncover a striking proportionality between the dominant magnon mode energies and the values. Our results suggest the Ru ions may have similar or the same magnetic phase in all pyrochlore ruthenates of our study. We have thus found an avenue for directly tuning the magnetic exchange interaction by the selection of the -site ion.- Open Access
- 11 August 2023
- Published by Springer Nature in npj Quantum Materials
- Vol. 8 (1) , 1-7
Collective magnetic Higgs excitation in a pyrochlore ruthenate
The emergence of scalar Higgs-type amplitude modes in systems where symmetry is spontaneously broken has been a highly successful, paradigmatic description of phase transitions, with implications ranging from high-energy particle physics to low-energy condensed matter systems. Here, we uncover two successive high temperature phase transitions in the pyrochlore magnet Nd2Ru2O7 at TN = 147 K and T* = 97 K, that lead to giant phonon instabilities and culminate in the emergence of a highly coherent excitation. This coherent excitation, distinct from other phonons and from conventional magnetic modes, stabilizes at a low energy of 3 meV. We assign it to a collective Higgs-type amplitude mode, that involves bond energy modulations of the Ru4 tetrahedra. Its striking two-fold symmetry, incompatible with the underlying crystal structure, highlights the possibility of multiple entangled broken symmetries.
- 11 August 2023
- Published by Springer Nature in npj Quantum Materials
- Vol. 8 (1) , 1-7
Open AccessCollective magnetic Higgs excitation in a pyrochlore ruthenate
The emergence of scalar Higgs-type amplitude modes in systems where symmetry is spontaneously broken has been a highly successful, paradigmatic description of phase transitions, with implications ranging from high-energy particle physics to low-energy condensed matter systems. Here, we uncover two successive high temperature phase transitions in the pyrochlore magnet Nd2Ru2O7 at TN = 147 K and T* = 97 K, that lead to giant phonon instabilities and culminate in the emergence of a highly coherent excitation. This coherent excitation, distinct from other phonons and from conventional magnetic modes, stabilizes at a low energy of 3 meV. We assign it to a collective Higgs-type amplitude mode, that involves bond energy modulations of the Ru4 tetrahedra. Its striking two-fold symmetry, incompatible with the underlying crystal structure, highlights the possibility of multiple entangled broken symmetries.
- 17 May 2021
- Published by Springer Nature in Journal of the Korean Physical Society
- Vol. 79 (2) , 173-184
Machine learning study of the deformed one-dimensional topological superconductor
- 17 May 2021
- Published by Springer Nature in Journal of the Korean Physical Society
- Vol. 79 (2) , 173-184
Machine learning study of the deformed one-dimensional topological superconductor