Gahee Lee
Postdoc
Gahee Lee
During my M.S. and Ph.D. studies, I developed low-temperature scanning tunneling microscopy (STM) systems and conducted experimental studies on Kagome and topological materials, along with the fabrication of two-dimensional devices. My research interests include electron correlations, topological phases, and unconventional superconductivity.
“좋은 질문을 하는 것이 좋은 답을 찾는 것보다 더 중요하다.”
-허준이-
- Education
- Work Experience
- Selected Publications
| 2026 PhD in Physics, Chung-Ang University, Seoul, Korea 2021 MS in Physics, Chung-Ang University, Seoul, Korea 2019 BS in Physics, Chung-Ang University, Seoul, Korea | |
| 2026 – Current | Postdoctoral Researcher at Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Ewha Womans University, Seoul, Korea |
2025
Gahee Lee J J
Direct Observation of Anisotropic Coulomb Interaction in a Topological Nodal Line Semimetal Journal Article
In: Advanced Science, vol. 12, iss. 8, no. 2407437, 2025.
@article{,
title = {Direct Observation of Anisotropic Coulomb Interaction in a Topological Nodal Line Semimetal},
author = {Gahee Lee, Hyo Won Kim, Junseo Jung,Taesu Park, Won-Jun Jang, Hoil Kim, Jun Sung Kim, Ji Hoon Shim, Bohm-Jung Yang, Sangjun Jeon},
url = {https://doi.org/10.1002/advs.202407437},
doi = {10.1002},
year = {2025},
date = {2025-01-07},
urldate = {2025-01-07},
journal = {Advanced Science},
volume = {12},
number = {2407437},
issue = {8},
abstract = {The fundamental characteristics of collective interactions in topological band structures can be revealed by the exploration of charge screening in topological materials. In particular, distinct anisotropic screening behaviors are predicted to occur in Dirac nodal line semimetals (DNLSMs) due to their peculiar anisotropic low-energy dispersion. Despite the recent extensive theoretical research, experimental observations of exotic charge screening in DNLSMs remain elusive, which is partly attributed to the coexisting trivial bands near the Fermi energy. This study reports the first direct observation of highly anisotropic charge-screening behavior in the DNLSM SrAs3. Through atomically resolved conductance measurements, a highly anisotropic charge-screening pattern around charged impurities on a surface is demonstrated. Moreover, the combination of model studies and first-principles calculations reveals the unique nature of the screening anisotropy in DNLSMs. The results of this study are expected to pave the way for understanding the profound collective behavior of interacting low-energy fermions in topological materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The fundamental characteristics of collective interactions in topological band structures can be revealed by the exploration of charge screening in topological materials. In particular, distinct anisotropic screening behaviors are predicted to occur in Dirac nodal line semimetals (DNLSMs) due to their peculiar anisotropic low-energy dispersion. Despite the recent extensive theoretical research, experimental observations of exotic charge screening in DNLSMs remain elusive, which is partly attributed to the coexisting trivial bands near the Fermi energy. This study reports the first direct observation of highly anisotropic charge-screening behavior in the DNLSM SrAs3. Through atomically resolved conductance measurements, a highly anisotropic charge-screening pattern around charged impurities on a surface is demonstrated. Moreover, the combination of model studies and first-principles calculations reveals the unique nature of the screening anisotropy in DNLSMs. The results of this study are expected to pave the way for understanding the profound collective behavior of interacting low-energy fermions in topological materials.
Gahee Lee J S; Jeon S
Design of a scanning tunneling microscope integrated with a glove box for measuring two-dimensional material flakes Journal Article
In: IOPScience, vol. 36, no. 7, 2025.
@article{nokey,
title = {Design of a scanning tunneling microscope integrated with a glove box for measuring two-dimensional material flakes},
author = {Gahee Lee, Jungin Yeo, Junyoung Sim, Subin Lee and Sangjun Jeon},
doi = {10.1088/1361-6501/ade333},
year = {2025},
date = {2025-07-03},
urldate = {2025-07-03},
journal = {IOPScience},
volume = {36},
number = {7},
abstract = {Two-dimensional (2D) materials and their heterostructures offer a rich platform for studying the fundamentals of condensed matter physics and engineering new functional devices. Scanning tunneling microscopy (STM) has revealed various atomic structures and electronic properties of 2D materials. However, STM measurements require atomically clean surfaces, which are difficult to maintain, as many 2D materials readily degrade upon air exposure. Moreover, the small size of exfoliated flakes, typically around 10 μm, presents a challenge for accurate and repeatable tip positioning in conventional STM systems. To overcome these limitations, we designed a home-built low-temperature STM integrated with a glove box and a specially designed sample stage. The glove box, directly connected to a load-lock chamber of STM system, enables the transfer and measurement of samples without exposure to ambient air, minimizing contamination and oxidation. The sample stage, designed with dual pockets and micron-level positioning capability, facilitate in-situ tip conditioning and precise navigation to small 2D flakes. The synergistic integration of these components ensures reliable, high-resolution STM/STS measurements, enabling comprehensive investigations into the electronic properties of a wide range of 2D materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Two-dimensional (2D) materials and their heterostructures offer a rich platform for studying the fundamentals of condensed matter physics and engineering new functional devices. Scanning tunneling microscopy (STM) has revealed various atomic structures and electronic properties of 2D materials. However, STM measurements require atomically clean surfaces, which are difficult to maintain, as many 2D materials readily degrade upon air exposure. Moreover, the small size of exfoliated flakes, typically around 10 μm, presents a challenge for accurate and repeatable tip positioning in conventional STM systems. To overcome these limitations, we designed a home-built low-temperature STM integrated with a glove box and a specially designed sample stage. The glove box, directly connected to a load-lock chamber of STM system, enables the transfer and measurement of samples without exposure to ambient air, minimizing contamination and oxidation. The sample stage, designed with dual pockets and micron-level positioning capability, facilitate in-situ tip conditioning and precise navigation to small 2D flakes. The synergistic integration of these components ensures reliable, high-resolution STM/STS measurements, enabling comprehensive investigations into the electronic properties of a wide range of 2D materials.
Gahee Lee C W
Emergence of Quasi-One-Dimensional van Hove Singularity in Kagome Metal RbV3Sb5 Journal Article
In: ACS Publications, 2025.
@article{nokey,
title = {Emergence of Quasi-One-Dimensional van Hove Singularity in Kagome Metal RbV3Sb5},
author = {Gahee Lee, Seongjoon Lim, Choongjae Won,Fei-Ting Huang,Bongsu Kim,Kun Woo Kim,Sang-Wook Cheong,Sangjun Jeon},
doi = {10.1021/acs.nanolett.5c04021},
year = {2025},
date = {2025-11-26},
journal = {ACS Publications},
abstract = {The divergence of the density of states (DOS) near the Fermi energy plays a critical role in strengthening electron correlations. van Hove singularities (vHS) are a common source of this DOS divergence, and their characteristics depend on the dimensionality of electron dispersion. The atomic arrangement on the surface can alter the effective dimensionality of electron dispersion and, consequently, vHS. In V-based Kagome metals AV3Sb5 (A = K, Rb, and Cs), the saddle-shaped dispersion results in two-dimensional vHS. Intriguingly, the surface arrangement of atoms in a Kagome lattice can reduce the effective dimensionality of electron dispersion, enhancing electron correlations. By taking advantage of nearly closed shell electronic character of Rb atoms, their linear arrangement imposes a one-dimensional localized potential on the underlying Kagome lattice. As a result, we observe a significantly increased divergence of DOS along with an augmentation of the charge density wave, potentially driven by reinforced electronic correlations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The divergence of the density of states (DOS) near the Fermi energy plays a critical role in strengthening electron correlations. van Hove singularities (vHS) are a common source of this DOS divergence, and their characteristics depend on the dimensionality of electron dispersion. The atomic arrangement on the surface can alter the effective dimensionality of electron dispersion and, consequently, vHS. In V-based Kagome metals AV3Sb5 (A = K, Rb, and Cs), the saddle-shaped dispersion results in two-dimensional vHS. Intriguingly, the surface arrangement of atoms in a Kagome lattice can reduce the effective dimensionality of electron dispersion, enhancing electron correlations. By taking advantage of nearly closed shell electronic character of Rb atoms, their linear arrangement imposes a one-dimensional localized potential on the underlying Kagome lattice. As a result, we observe a significantly increased divergence of DOS along with an augmentation of the charge density wave, potentially driven by reinforced electronic correlations.