Hongki Min, Ph.D.  [CV]
Associate Professor
Department of Physics and Astronomy
Seoul National University

OfficeRLM 7.320 / +1-512-471-9412
E-mail hongki@physics.utexas.edu
Homepage www.ph.utexas.edu/~hongki
Country Republic of Korea
Office216-A251 / +1-301-975-4328
E-mail hongki.min@nist.gov , hongki@physics.utexas.edu
Homepage www.ph.utexas.edu/~hongki
Country Republic of Korea
Office :  Room 2121, Physics Building / +1-301-405-7652
E-mail hmin@umd.edu , hongki@physics.utexas.edu
Homepage www.ph.utexas.edu/~hongki
Country Republic of Korea
OfficeBuilding 56, Room 506
Phone :  +82-2-880-4270
E-mail hmin@snu.ac.kr
Homepage physics.snu.ac.kr/hmin
Country Republic of Korea

Education

Ph.D. (Physics)
The University of Texas at Austin (2001.8-2008.8)
Advisor : Prof. Allan H. MacDonald
Thesis : Possible ordered states in graphene systems  [corrections]
B.S. (Physics)
Seoul National University (1995.3-2001.2)

Professional Experience

Associate Professor
Department of Physics and Astronomy, Seoul National University (2015.9-present)
Visiting Scholar
Department of Physics and Astronomy, University of Pennsylvania (2016.2-2017.1)
Assistant Professor
Department of Physics and Astronomy, Seoul National University (2011.9-2015.8)
Postdoctoral Researcher
Prof. Sankar Das Sarma, University of Maryland (2010.9-2011.8)
Postdoctoral Researcher
Dr. Mark D. Stiles, National Institute of Standards and Technology (2008.9-2010.8)
Grader/Research Assistant
Prof. Allan H. MacDonald, The University of Texas at Austin (2001.8-2008.8)
Military Service
Korean Augmentation to the US Army, Sergeant (1997.8-1999.9)

Research Interests

    My primary research interest is modeling condensed matter systems using analytical and numerical approaches, and I have an interest in material properties which may prove to have technological value. My technical experience covers various tools used in condensed matter theory, ranging from numerical electronic structure calculations to more analytical field theoretical approaches.
    During my Ph.D. studies done under the supervision of Dr. Allan H. MacDonald at the University of Texas at Austin, first we investigated the influence of spin-orbit coupling on monolayer graphene and the energy gap opening by applying an external electric field in bilayer graphene using a tight-binding model and ab initio electronic structure calculations. Next, we studied the electronic structure of multilayer graphene and developed a simple diagrammatic method to analyze the low energy properties of arbitrarily stacked graphene sheets. The result showed that at low energies, arbitrarily stacked multilayer graphene is described by a set of pseudospin doublets with a conserved chirality sum, which predicts a new quantized Hall conductivity. This emergent chiral symmetry is the origin of the universal optical conductivity in both low and high frequency limits, and we proposed an optical method to identify the stacking sequences. We also studied effects of electron-electron interactions and possible ordered states. Using a mean-field theory and perturbative renormalization group theory, we predicted that neutral graphene bilayers are pseudospin magnets, in which the charge density contribution from each spin and valley spontaneously shifts to one of the two layers. Furthermore, we demonstrated that room-temperature excitonic condensation is possible in graphene double layers, suggesting new electronic device applications based on unusual collective transport of bilayer excitonic condensates.
    After moving to NIST as a postdoctoral researcher working with Dr. Mark D. Stiles, I extended my research to the area of spintronics focusing on the effects of disorder on magnetic domain wall dynamics. We performed micromagnetic simulations in the presence of extrinsic random potential and studied the dynamics of vortex wall propagation driven by fields or currents, and vortex gyration driven by magnetic field pulses. We found that the dynamics in the presence of disorder can be understood in terms of an effective damping that increases with the disorder due to the excitement of the internal degrees of freedom in the vortex structure. Next, I joined Dr. Sankar Das Sarma's group at University of Maryland as a postdoctoral researcher. I focused on various electronic, transport and many-body properties in two-dimensional electron systems including graphene and GaAs heterostructures investigating effects of phonons, disorder and electron-electron interactions on the transport and thermodynamic properties.
    After I joined the Department of Physics and Astronomy at Seoul National University as a faculty member, I am focusing on electronic & topological properties and interaction effects in two-dimensional layered structures and in three-dimensional Dirac materials. We expect that the interplay between the chiral electronic structure and electron-electron interactions lead to many interesting physics. Currently we are looking for interaction induced collective phenomena and ordered states in these systems such as plasmons, plasmon-polaritons, excitons, exciton-polaritons and superconductivity. Because of the collective behavior of many electrons, the thermal smearing of the switching behavior using these states can be significantly reduced, potentially enabling electronic devices consuming much less power and easily controllable. This suggests the possibility of a new electronic device scheme called pseudospintronics.

Publications [arXiv, Google Scholar]

  • Electrodynamics on Fermi cyclides in nodal line semimetals
    Seongjin Ahn, E. J. Mele, and Hongki Min
    arXiv:1703.00130 (2017)
  • Mapping of Bernal and non-Bernal stacking domains in bilayer graphene using infrared nanoscopy
    Gyouil Jeong, Boogeon Choi, Deok-Soo Kim, Seongjin Ahn, Baekwon Park, Jin Hyoun Kang, Hongki Min, Byoung-Hee Hong, and Zee Hwan Kim
    Nanoscale 9, 4191 (2017)
  • Ferromagnetism in chiral multilayer two-dimensional semimetals
    Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 95, 155414 (2017), arXiv:1702.01859
  • Semiclassical Boltzmann transport theory for multi-Weyl semimetals
    Sanghyun Park, Seungchan Woo, E. J. Mele, and Hongki Min
    Phys. Rev. B 95, 161113(R) (2017), arXiv:1701.07578
  • Broken sublattice symmetry states in Bernal stacked multilayer graphene
    Chiho Yoon, Yunsu Jang, Jeil Jung, and Hongki Min
    2D Mater. 4, 021025 (2017), arXiv:1610.07105
  • Large negative differential transconductance in multilayer graphene: the role of intersubband scattering
    Seungchan Woo, E. H. Hwang, and Hongki Min
    2D Mater. 4, 025090 (2017), arXiv:1610.07006
  • Optical conductivity of multi-Weyl semimetals
    Seongjin Ahn, E. J. Mele, and Hongki Min
    Phys. Rev. B 95, 161112(R) (2017), arXiv:1609.08566
  • Zero-line modes at stacking faulted domain walls in multilayer graphene
    Changhee Lee, Gunn Kim, Jeil Jung, and Hongki Min
    Phys. Rev. B 94, 125438 (2016), arXiv:1607.01641
  • Collective modes in multi-Weyl semimetals
    Seongjin Ahn, E. H. Hwang, and Hongki Min
    Scientific Reports 6, 34023 (2016), arXiv:1604.02989
  • Stacking dependence of carrier-interactions in multilayer graphene systems
    Yunsu Jang, E. H. Hwang, A. H. MacDonald, and Hongki Min
    Phys. Rev. B 92, 041411(R) (2015), arXiv:1503.00212
  • Stacking structures of few-layer graphene revealed by phase-sensitive infrared nanoscopy
    Deok-Soo Kim, Hyeoksang Kwon, Alexey Yu. Nikitin, Seongjin Ahn, Luis Martin-Moreno, Francisco J. Garcia-Vidal, Sun-Min Ryu, Hongki Min, and Zee Hwan Kim
    ACS Nano 9, 6765 (2015)
  • Carrier screening, transport, and relaxation in three-dimensional Dirac semimetals
    S. Das Sarma, E. H. Hwang, and Hongki Min
    Phys. Rev. B 91, 035201 (2015), arXiv:1408.0518
  • Inelastic carrier lifetime in a coupled graphene/electron-phonon system: Role of plasmon-phonon coupling
    Seongjin Ahn, E. H. Hwang, and Hongki Min
    Phys. Rev. B 90, 245436 (2014), arXiv:1409.8394
  • Transport gap in dual-gated graphene bilayers using oxides as dielectrics
    Kayoung Lee, Babak Fallahazad, Hongki Min, and Emanuel Tutuc
    IEEE Transactions on Electron Devices 60, 103 (2013)
  • Competing ordered states in bilayer graphene
    Fan Zhang, Hongki Min, and A. H. MacDonald
    Phys. Rev. B 86, 155128 (2012), arXiv:1205.5532
  • Interplay between phonon and impurity scattering in two-dimensional hole transport
    Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 86, 085307 (2012), arXiv:1203.1929
  • Polarizability and screening in chiral multilayer graphene
    Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 86, 081402(R) (2012), arXiv:1202.2132
  • Comparison of microscopic models for disorder in bilayer graphene: Implications for the density of states and the optical conductivity
    D. S. L. Abergel, Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 85, 045411 (2012), arXiv:1109.5702
  • dμ/dn in suspended bilayer graphene: the interplay of disorder and band gap
    D. S. L. Abergel, Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 84, 195423 (2011), arXiv:1107.4100
  • Edge saturation effects on the magnetism and band gaps in multilayer graphene ribbons and flakes
    Bhagawan Sahu, Hongki Min, and Sanjay K. Banerjee
    Phys. Rev. B 84, 075481 (2011), arXiv:1104.4354
  • Optical and transport gaps in gated bilayer graphene
    Hongki Min, D. S. L. Abergel, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 84, 041406(R) (2011), arXiv:1104.0938
  • Landau levels and band bending in few-layer epitaxial graphene
    Hongki Min, Shaffique Adam, Young Jae Song, Joseph A. Stroscio, M. D. Stiles, and A. H. MacDonald
    Phys. Rev. B 83, 155430 (2011), arXiv:1101.2454
  • Semiclassical Boltzmann transport theory for graphene multilayers
    Hongki Min, Parakh Jain, Shaffique Adam, and M. D. Stiles
    Phys. Rev. B 83, 195117 (2011), arXiv:1012.5820
  • Chirality-dependent phonon-limited resistivity in multiple layers of graphene
    Hongki Min, E. H. Hwang, and S. Das Sarma
    Phys. Rev. B 83, 161404(R) (2011), arXiv:1011.0741
  • Effects of disorder on magnetic vortex gyration
    Hongki Min, Robert D. McMichael, Jacques Miltat, and M. D. Stiles
    Phys. Rev. B 83, 064411 (2011), arXiv:1102.3711
  • High-resolution tunnelling spectroscopy of a graphene quartet
    Y. J. Song, A. F. Otte, Y. Kuk, Y. Hu, D. B. Torrance, P. N. First, W. A. de Heer, Hongki Min, S. Adam, M. D. Stiles, A. H. MacDonald, and J. A. Stroscio
    Nature 467, 185 (2010)
  • Effects of edge magnetism and external electric field on energy gaps in multilayer graphene nanoribbons
    Bhagawan Sahu, Hongki Min, and Sanjay K. Banerjee
    Phys. Rev. B 82, 115426 (2010), arXiv:1006.3572
  • Band structure of ABC-stacked graphene trilayers
    Fan Zhang, Bhagawan Sahu, Hongki Min, and A. H. MacDonald
    Phys. Rev. B 82, 035409 (2010), arXiv:1004.1481
  • Effects of disorder and internal dynamics on vortex wall propagation
    Hongki Min, Robert D. McMichael, Michael J. Donahue, Jacques Miltat, and M. D. Stiles
    Phys. Rev. Lett. 104, 217201 (2010), arXiv:1003.1128, NIST Tech Beat
  • Effects of magnetism and electric field on the energy gap of bilayer graphene nanoflakes
    Bhagawan Sahu, Hongki Min, and Sanjay Banerjee
    Phys. Rev. B 81, 045414 (2010), arXiv:0910.2719
  • Spontaneous inversion symmetry breaking in graphene bilayers
    Fan Zhang, Hongki Min, Marco Polini, and A. H. MacDonald
    Phys. Rev. B 81, 041402(R) (2010), arXiv:0907.2448, Physics Viewpoint
  • Origin of universal optical conductivity and optical stacking sequence identification in multilayer graphene
    Hongki Min and A. H. MacDonald
    Phys. Rev. Lett. 103, 067402 (2009), arXiv:0903.2163
  • Quantum wells in polar-nonpolar oxide heterojunction systems
    C.-C Joseph Wang, Bhagawan Sahu, Hongki Min, Wei-Cheng Lee, and A. H. MacDonald
    Phys. Rev. B 79, 115408 (2009), arXiv:0810.0798
  • Comment on "Electron screening and excitonic condensation in double-layer graphene systems"
    Rafi Bistritzer, Hongki Min, Jung-Jung Su, and A. H. MacDonald
    Comment on Phys. Rev. B 78, 241401(R) (2008), arXiv:0810.0331
  • Electronic structure of multilayer graphene
    Hongki Min and A. H. MacDonald
    Prog. Theor. Phys. Suppl. 176, 227 (2008), arXiv:0806.2792
  • Room-temperature superfluidity in graphene bilayers
    Hongki Min, Rafi Bistritzer, Jung-Jung Su, and A. H. MacDonald
    Phys. Rev. B 78, 121401(R) (2008), arXiv:0802.3462, Nanotechweb News
  • Energy gaps, magnetism, and electric field effects in bilayer graphene nanoribbons
    Bhagawan Sahu, Hongki Min, A. H. MacDonald, and Sanjay Banerjee
    Phys. Rev. B 78, 045404 (2008), arXiv:0801.1991
  • Chiral decomposition in the electronic structure of graphene multilayers
    Hongki Min and A. H. MacDonald
    Phys. Rev. B 77, 155416 (2008), arXiv:0711.4333
  • Pseudospin magnetism in graphene
    Hongki Min, Giovanni Borghi, Marco Polini, and A. H. MacDonald
    Phys. Rev. B 77, 041407(R) (2008), arXiv:0707.1530, Nanotechweb News
  • Ab initio theory of gate induced gaps in graphene bilayers
    Hongki Min, Bhagawan Sahu, Sanjay K. Banerjee, and A. H. MacDonald
    Phys. Rev. B 75, 155115 (2007), arXiv:cond-mat/0612236
  • Intrinsic and Rashba spin-orbit interactions in graphene sheets
    Hongki Min, J. E. Hill, N. A. Sinitsyn, B. R. Sahu, Leonard Kleinman, and A. H. MacDonald
    Phys. Rev. B 74, 165310 (2006), arXiv:cond-mat/0606504
  • Charge and spin Hall conductivity in metallic graphene
    N. A. Sinitsyn, J. E. Hill, Hongki Min, Jairo Sinova, and A. H. MacDonald
    Phys. Rev. Lett. 97, 106804 (2006), arXiv:cond-mat/0602598
  • Books

  • Electronic properties of multilayer graphene
    Chapter 11 in Graphene nanoelectronics: Metrology, synthesis, properties and applications
    Editor: H. Raza, Springer (March 2012)
  • Possible Ordered States in Graphene Systems: Electronic Structure, Pseudospin Magnetism and Exciton Condensation
    Hongki Min, VDM Verlag (May 2009)
  • Current Status

        From September 2011, I joined the Department of Physics and Astronomy at Seoul National University as a faculty member.

    Classes

  • Condensed Matter Physics 1,2 (Graduate)
    Spring 2017
  • Many-body Physics 1,2 (Graduate)
    Spring 2015, Fall 2015
  • Quantum Physics 1,2 (Undergraduate)
    Spring 2012, Fall 2012, Spring 2013, Fall 2013, Spring 2014, Fall 2014
  • Advanced Topics in Condensed Matter Physics: Graphene (Graduate)
    Fall 2012
  • Group members

  • Seongjin Ahn (sjahn@snu.ac.kr)
  • Seung Chan Woo (silkian@snu.ac.kr)
  • Changhee Lee (changhee900820@gmail.com)
  • Chiho Yoon (yooon@snu.ac.kr)
  • Sanghyun Park (signfang@gmail.com)