Publications – Ko group webpage

^†Contributed equally, ^*Corresponding author

Submitted

W.-J. Jang^†, H. Noh^†, S.-H. Kang, W. Ko, M. J. Park^*, and H. W. Kim^*, “Hierarchical First-order and Second-order Topological States in Symmetry-Controllable Grain Boundary,” (submitted)

S. Y. Song, C. Hua, G. B. Halász, W. Ko, J. Yan, B. J. Lawrie, and P. Maksymovych^*, “Nanoscale control over single vortex motion in an unconventional superconductor,” (submitted)

W. Ko^†, S.-H. Kang^†, J. Lapano, H. Chang, J. Teeter, M. Brahlek, M. Yoon^*, R. G. Moore^*, and A.-P. Li^*, “Interplay between Topological States and Rashba States as Manifested on Surface Steps at Room Temperature,” arXiv:2301.06266 (submitted)

M. Zohair, N. Moehring, P. Cheng, J. Eaves-Rathert, E. Brody, J. Warner, W. Ko, A.-P. Li, P. Kidambi, and C. Pint^*, “Nanoporous Graphene Modified Separators Enable Early Dendrite Detection for Safe Lithium and Magnesium Batteries,” (submitted)

2023

F. Lüpke^†, M. Kolmer^†, J. Yan, H. Chang, P. Vilmercati, H. Weitering, W. Ko^*, and A.-P. Li^*, “Anti-site defect-induced disorder in compensated topological magnet MnBi_2-xSb_xTe₄,” Commun. Mater. 4 82 (2023)

W. Ko^†, S. Y. Song^†, J. Yan, J. L. Lado, and P. Maksymovych^*, “Atomic-scale Andreev probe of unconventional superconductivity,” Nano Lett. 23 8310 (2023)

S. Y. Song, C. Hua, L. Bell, W. Ko, H. Fangohr, J. Yan, G. B. Halász, E. F. Dumitrescu, B. J. Lawrie, and P. Maksymovych^*, “Nematically templated vortex lattices in superconducting FeSe,” Nano Lett. 23 2822 (2023)

W. Ko, Z. Gai, A. Puretzky, L. Liang, T. Berlijn, J. Hachtel, K. Xiao, P. Ganesh, M. Yoon, and A.-P. Li^*, “Understanding Heterogeneities in Quantum Materials (review paper),” Adv. Mater. 35 2106909 (2023)

Before UTK (~2022)

M. Kolmer^*, W. Ko, J. Hall, S. Chen, J. Zhang, H. Zhao, L. Ke, C.-Z. Wang, A.-P. Li, and M. C. Tringides, “Breaking of Inversion Symmetry and Interlayer Electronic Coupling in Bilayer Graphene Heterostructure by Structural Implementation of High Electric Displacement Fields,” J. Phys. Chem. Lett. 13 11571 (2022)

[Selected as the Front Cover of the issue: https://pubs.acs.org/toc/jpclcd/13/49]

M. S. Kavrik^†*, J. Hachtel^†*, W. Ko^†*, C. Qian, A. Abelson, E. B. Unlu, H. Kashyap, A.-P. Li, J.-C. Idrobo, and M. Law^*, “Emergence of Distinct Electronic States in Epitaxially-Fused PbSe Quantum Dot Superlattices,” Nat. Commun. 13 6802 (2022)

P. Cheng, F. Fornasiero, M. L. Jue, W. Ko, A.-P. Li, J. C. Idrobo, M. S. H. Boutilier, and P. R. Kidambi^*, “Differences in Water and Vapor Transport through Angstrom-scale Pores in Atomically Thin Membranes,” Nat. Commun. 13 6709 (2022)

[Selected as Editors’ Highlights of “Materials science and chemistry” section: https://www.nature.com/collections/eecgdgijhh]

N. K. Moehring, P. Chaturvedi, P. Cheng, W. Ko, A.-P. Li, M. S. H. Boutilier, and P. R. Kidambi^*, “Kinetic Control of Angstrom-Scale Porosity in 2D Lattices for Direct Scalable Synthesis of Atomically Thin Proton Exchange Membranes,” ACS Nano 16 16003 (2022)

Q. Zou, S. Huang, W. Ko, M. Fu, Y. Yang, K. Zhao, S. R. Crittenden, E. W. Plummer, R. Jin^*, and Z. Gai^*, “Exploration of two surfaces observed in Weyl semimetal BaMnSb₂,” npj Quantum Mater. 7 85 (2022)

W. Ko, J. L. Lado, and P. Maksymovych^*, “Non-contact Andreev reflection as a direct probe of superconductivity on the atomic scale,” Nano Lett. 22 4042 (2022)

[Highlighted in Aalto University News: https://www.aalto.fi/en/news/an-atomic-scale-window-into-superconductivity-paves-the-way-for-new-quantum-materials, Phys.org: https://phys.org/news/2022-06-atomic-scale-window-superconductivity-paves-quantum.html, and Journal of Spanish Physics Society cover http://revistadefisica.es/index.php/ref/issue/current]

S.-H. Kang^†, S. Jeon^*, H.-J. Kim, W. Ko, S. Cho, S. H. Kang, S. W. Kim, H. Yang, H. W. Kim^*, and Y.-W. Son^*, “Coulomb interaction-driven reshaped Weyl fermionic dispersions in MoTe₂,” Phys. Rev. B 105 045143 (2022)

F. Lüpke, A. D. Pham, Y.-F. Zhao, L.-J. Zhou, W. Lu, E. Briggs, J. Bernholc, M. Kolmer, J. Teeter, W. Ko, C.-Z. Chang, P. Ganesh^*, and A.-P. Li^*, “Local manifestations of thickness dependent topology and axion edge state in topological magnet MnBi₂Te₄,” Phys. Rev. B 105 035423 (2022)

K. Wang, L. Zhang, G. D. Nguyen, X. Sang, C. Liu, Y. Yu, W. Ko, R. R. Unocic, A. A. Puretzky, C. M. Rouleau, D. B. Geohegan, G. Duscher, A.-P. Li, M. Yoon, and K. Xiao^*, “Selective Antisite Defect Formation in WS₂ Monolayers via Reactive Growth on Dilute W-Au Alloy Substrates,” Adv. Mater. 34 2106674 (2022)

[Selected as Frontispiece of Advanced Materials 3/2022: https://onlinelibrary.wiley.com/doi/10.1002/adma.202270024]

W. Ko, E. F. Dumitrescu, and P. Maksymovych^*, “Statistical detection of Josephson, Andreev, and single quasiparticle currents in scanning tunneling microscopy,” Phys. Rev. Res. 3 033248 (2021)

J. Lapano, O. Dyck, A. Lupini, W. Ko, H. Li, H. Miao, H. N. Lee, A.-P. Li, M. Brahlek, S. Jesse, R. G. Moore^*, “Van der Waals Epitaxy Growth of Bi₂Se₃ on a Freestanding Monolayer Graphene Membrane: Implications for Layered Materials and Heterostructures,” ACS Appl. Nano Mater. 4 7607 (2021)

H. W. Kim, I. Jeon, W. Ko^*, and S. H. Kim^*, “Unidirectional Growth of Graphene Nano-Islands from Carbon Cluster Seeds on Ge(110),” App. Surf. Sci. 536 147722 (2021)

S. M. Hus, R. Ge, P.-A. Chen, M.-H. Chiang, G. Donnelly, W. Ko, F. Huang, L. Liang, A.-P. Li, and D. Akinwande^*, “Observation of single-defect memristor in an MoS₂ atomic sheet,” Nat. Nanotechnol. 16 58 (2021)

[Highlighted in ORNL News: https://www.ornl.gov/research-highlight/observation-single-defect-memristor-mos2-atomic-sheet]

W. Ko, M. Kolmer, J. Yan, A. D. Pham, M. Fu, F. Lüpke, S. Okamoto, Z. Gai, P. Ganesh, and A.-P. Li^*, “Realizing gapped surface states in magnetic topological insulator MnBi_2-xSb_xTe₄,” Phys. Rev. B 102 115402 (2020)

W. Ko^†*, H. W. Kim^†, Y. Cho, J. Ku, H. Kwon, Y. Oh, J.-W. Jung, I. Jeon, H. Suh, Y. Kuk, and S. W. Hwang, “Magnetic states of atomic vacancies in graphite probed by scanning tunneling microscopy,” AIP Adv. 10 085325 (2020)

P. Cheng, M. M. Kelly, N. K. Moehring, W. Ko, A.-P. Li, J. C. Idrobo, M. S. H. Boutilier, and P. R. Kidambi^*, “Tailoring Sub-nanometer Pore Size Distributions in Atomically Thin Graphene Membranes for Desalination and Molecular Separations,” Nano Lett. 20 5951 (2020)

H. W. Kim^†*, S.-H. Kang^†, H.-J. Kim^†, K. Chae, S. Cho, W. Ko, S. Jeon, S. H. Kang, H. Yang, S. W. Kim, S. Park, S. Hwang, Y.-K. Kwon, and Y.-W. Son^*, “Symmetry dictated grain boundary state in a two-dimensional topological insulator,” Nano Lett. 20 5837 (2020)

M. Kolmer, A. K. Steiner, I. Izydorczyk, W. Ko, M. Engelund, M. Szymonski, A.-P. Li^*, and K. Amsharov^*, “Rational synthesis of atomically precise graphene nanoribbons directly on metal oxide surfaces,” Science 369 571 (2020)

[Highlighted in ORNL News: https://www.ornl.gov/news/surface-synthesis-graphene-nanoribbons-could-advance-quantum-devices, and Phys.org: https://phys.org/news/2020-10-on-surface-synthesis-graphene-nanoribbons-advance.html]

G. D. Nguyen, A. D. Oyedele, A. Haglund, W. Ko, L. Liang^*, A. A. Puretzky, D. Mandrus, K. Xiao, and A.-P. Li^*, “Atomically Precise PdSe2 Pentagonal Nanoribbons,” ACS Nano 14 1951-1957 (2020)

N. Briggs, B. Bersch, Y. Wang, J. Jiang, R. Koch, N. Nayir, K. Wang, M. Kolmer, W. Ko, A. de la Fuente Duran, S. Subramanian, C. Dong, J. Shallenberger, M. Fu, Q. Zou, Y.-W. Chuang, Z. Gai, A.-P. Li, A. Bostwick, C. Jozwiak, C.-Z. Chang, E. Rotenberg, J. Zhu, A. van Duin, V. Crespi, and J. Robinson^*, “Atomically thin half-van der Waals metals enabled by confinement heteroepitaxy,” Nat. Mater. 19 637 (2020)

[Highlighted in ORNL News: https://www.ornl.gov/research-highlight/atomically-thin-half-van-der-waals-metals-enabled-confinement-heteroepitaxy]

J. W. Kim, T.-S. Ju, S. Song, D. Lee, S. Y. Cho, S. D. Bu, W. Ko, A.-P. Li, J. Park^*, and S. Park^*, “Enhancing the Local Conductivity of Cu Films Using Temperature-Assisted Agglomerated Cu Nanostructures,” J. Phys. D: Appl. Phys. 53 09LT02 (2020)

W. Ko, C. Ma, G. D. Nguyen, M. Kolmer, and A.-P. Li^*, “Atomic-Scale Manipulation and In Situ Characterization with Scanning Tunneling Microscopy (review paper),” Adv. Funct. Mater. 29 1903770 (2019)

A. L. Miettinen, M. S. Nevius, W. Ko, M. Kolmer, A.-P. Li, M. N. Nair, B. Kierren, L. Moreau, E. H. Conrad^*, and A. Tejeda, “Edge States and Ballistic Transport in Zig-zag Graphene Ribbons: The Role of SiC Polytypes,” Phys. Rev. B 100 045425 (2019)

M. H. Lee, J. H. Yun, G. Kim, J. E. Lee, S.-D. Park, H. Reith, G. Schierning, K. Nielsch, W. Ko, A.-P. Li, and J.-S. Rhyee^*, “Synergetic Enhancement of Thermoelectric Performance by Selective Charge Anderson Localization-Delocalization Transition in n-Type Bi-Doped PbTe/Ag₂Te Nanocomposite,” ACS Nano 13 3806 (2019)

H. W. Kim^*, W. Ko, W.-J. Joo, Y. Cho, Y. Oh, J. Ku, I. Jeon, S. Park, and S. W. Hwang^*, “Unraveling the Structural and Electronic Properties of Graphene/Ge(110),” J. Phys. Chem. Lett. 9 7059 (2018)

W. Ko, G. D. Nguyen, H. Kim, J. S. Kim, X.-G. Zhang, and A.-P. Li^*, “Accessing the intrinsic spin transport in a topological insulator by controlling the crossover of bulk-to-surface conductance,” Phys. Rev. Lett. 121 176801 (2018)

[Highlighted in DOE Office of Science: https://www.energy.gov/science/bes/articles/channeling-electrons-ultrafast-spin-conductivity, https://www.eurekalert.org/features/doe/2020-02/drnl-cef020520.php]

C.-S. Lee, K. W. Shin, H.-J. Song, H. Park, Y. Cho, D.-H. Im, H. Lee, J.-H. Lee, J. Y. Won, J. G. Chung, C. Kim, K.-E. Byun, E.-K. Lee, Y. Kim, W. Ko, H. J. Lim, S. Park^*, and H.-J. Shin^*, “Fabrication of metal/graphene hybrid interconnects by direct graphene growth and their integration properties,” Adv. Electron. Mater. 4 1700624 (2018)

W. Ko, S. M. Hus, X. Li, T. Berlijn, G. D. Nguyen, K. Xiao, and A.-P. Li^*, “Tip-induced local strain on MoS₂/graphite detected by inelastic electron tunneling spectroscopy,” Phys. Rev. B 97 125401 (2018)

H. W. Kim^†*, W. Ko^†, J. Ku, Y. Kim, S. Park, and S. W. Hwang, “Evolution of graphene growth on Pt(111): From carbon clusters to nanoislands,” J. Phys. Chem. C 121 25074 (2017)

H. Kwon^†, K. Lee^†, J. Heo, Y. Oh, H. Lee, S. Appalakondaiah, W. Ko, H. W. Kim, J.-W. Jung, H. Suh, H. Min, I. Jeon^*, E. Hwang^*, and S. W. Hwang, “Characterization of edge contact: Atomically resolved semiconductor-metal lateral boundary in MoS2,” Adv. Mater. 29 1702931 (2017)

H. W. Kim^*, J. Ku, W. Ko, Y. Cho, I. Jeon, and S. W. Hwang, “Quenching of the resonant states of single carbon vacancies in graphene/Pt(111),” J. Phys. Chem. C 121 24641 (2017)

S. M. Hus, X.-G. Zhang, G. D. Nguyen, W. Ko, A. P. Baddorf, Y. P. Chen, and A.-P. Li^*, “Detection of the spin-chemical potential in topological insulators using spin-polarized four-probe STM,” Phys. Rev. Lett. 119 137202 (2017)

Y. Oh^*, Y. Cho, H. Kwon, J. Lee, I. Jeon, W. Ko, H. W. Kim, J. Ku, G. Kim, H. Suh^*, and S. W. Hwang, “Electronic structure and switching behavior of the metastable silicene domain boundary,” Appl. Phys. Lett. 110 263112 (2017)

S. Cho^†, S. H. Kang^†, H. S. Yu, H. W. Kim, W. Ko, S. W. Hwang, W. H. Han, D. H. Choe, Y. H. Jung, K. J. Chang, Y. H. Lee^*, H. Yang^*, and S. W. Kim^*, “Te vacancy-driven superconducting transition in orthorhombic molybdenum ditellurides,” 2D Mater. 4 021030 (2017)

W. Ko^*, J. Park, I. Jeon, H. W. Kim, H. Kwon, Y. Oh, J. S. Kim, H. Suh^*, S. W. Hwang, and C. Chung, “Local potential fluctuation of topological surface states in Bi_1.5Sb_0.5Te_1.7Se_1.3 observed by Landau level spectroscopy,” Appl. Phys. Lett. 108 083109 (2016)

H. W. Kim^†, W. Ko^†, J. Ku, I. Jeon, D. Kim, H. Kwon, Y. Oh, S. Ryu, Y. Kuk, S. W. Hwang, and H. Suh^*, “Nanoscale control of phonon excitation in graphene nanobubbles,” Nat. Commun. 6 7528 (2015)

H. W. Kim, J. Ku, W. Ko, I. Jeon, H. Kwon, S. Ryu, S.-J. Kahng, S.-H. Lee, S. W. Hwang, and H. Suh^*, “Strong interaction between graphene edge and metal revealed by scanning tunneling microscopy,” Carbon 78 190 (2014)

W. Ko, I. Jeon, H. W. Kim, H. Kwon, S.-J. Kahng, J. Park, J. S. Kim^*, S. W. Hwang, and H. Suh^*, “Atomic and electronic structure of an alloyed topological insulator, Bi_1.5Sb_0.5Te_1.7Se_1.3,” Sci. Rep. 3 2656 (2013)

K. K. Gomes^†, W. Mar^†, W. Ko^†, F. Guinea and H. C. Manoharan^*, “Designer Dirac fermions and topological phases in molecular graphene,” Nature 483 306 (2012)

S. Lee, M. F. Toney, W. Ko, J. C. Randel, H. J. Jung, K. Munakata, J. Lu, T. H. Geballe, M. R. Beasley, R. Sinclair, H. C. Manoharan and A. Salleo^*, “Laser-synthesized epitaxial graphene,” ACS Nano 4 7524 (2010)

K. K. Gomes^†, W. Ko^†, W. Mar^†, Y. Chen, Z. X. Shen and H. C. Manoharan^*, “Quantum imaging of topologically unpaired spin-polarized Dirac fermions,” arXiv:0909.0921

C. R. Moon, B. K. Foster, L. S. Mattos, G. Zeltzer, W. Ko and H. C. Manoharan^*, “Quantum geometry and phase extraction in isospectral electronic nanostructures,” Science 319 782 (2008)

H. Hayashi, W. Ko, T. Itahashi, A. Sagara, K. M. Itoh^*, L. S. Vlasenko^* and M. P. Vlasenko, “Dynamic nuclear polarization of 29Si nuclei in the isotope enriched n-type silicon,” Phys. Stat. Sol. (c) 3 4388 (2006)