Minkyung Han
Ph.D. Student in Earth and Planetary Sciences, admitted Summer 2021
All Publications
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Superconductivity in compressed quasi-one-dimensional face-sharing hexagonal perovskite chalcogenides.
Science advances
2025; 11 (37): eadv1894
Abstract
Oxide perovskite superconductors typically feature stacks of metal-oxygen octahedra or planar blocks connected through corners, forming three-dimensional (3D) or 2D layered structures. Here, we find a group of quasi-1D superconducting materials among hexagonal perovskite chalcogenides with face-sharing connectivity. Resistance and magnetization measurements demonstrate anisotropic superconductivity in compressed barium titanium trisulfide (BaTiS3) at a low hole carrier concentration of (1.6 ± 0.1) × 1021 per cubic centimeter, with the highest superconducting temperature (Tc) reaching ~9.3 kelvin. Synchrotron x-ray diffraction indicates that the superconducting phase retains a hexagonal perovskite structure consisting of quasi-1D infinite titanium hexasulfide chains. Density functional theory calculations, combined with the observed decrease in the maximum Tc from ~9.3 to ~6.2 kelvin upon substituting sulfur with selenium, suggest that electron-phonon interactions play a key role in the pairing mechanism of superconducting BaTiX3 (X = sulfur and selenium). Our study offers a quasi-1D platform with face-sharing metal-chalcogen octahedra for understanding the mechanism of emerging electronic states in perovskite materials.
View details for DOI 10.1126/sciadv.adv1894
View details for PubMedID 40938990
View details for PubMedCentralID PMC12429050
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Improving the creation of SiV centers in diamond via sub-μs pulsed annealing treatment.
Nature communications
2024; 15 (1): 7251
Abstract
Silicon-vacancy (SiV) centers in diamond are emerging as promising quantum emitters in applications such as quantum communication and quantum information processing. Here, we demonstrate a sub-μs pulsed annealing treatment that dramatically increases the photoluminescence of SiV centers in diamond. Using a silane-functionalized adamantane precursor and a laser-heated diamond anvil cell, the temperature and energy conditions required to form SiV centers in diamond were mapped out via an optical thermometry system with an accuracy of ±50 K and a 1 μs temporal resolution. Annealing scheme studies reveal that pulsed annealing can obviously minimize the migration of SiV centers out of the diamond lattice, and a 2.5-fold increase in the number of emitting centers was achieved using a series of 200-ns pulses at a 50 kHz repetition rate via acousto-optic modulation. Our study provides a novel pulsed annealing treatment approach to improve the efficiency of the creation of SiV centers in diamond.
View details for DOI 10.1038/s41467-024-51523-2
View details for PubMedID 39179592
View details for PubMedCentralID 7097076
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Machine learning-empowered study of metastable γ-CsPbI<sub>3</sub> under pressure and strain
JOURNAL OF MATERIALS CHEMISTRY A
2024
View details for DOI 10.1039/d4ta00174e
View details for Web of Science ID 001199652300001