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Research

Our group's research is directed towards utilizing a combination of materials synthesis, ambient pressure characterization, and high pressure and high magnetic field measurements to advance our understanding of novel and potentially useful electronic and magnetic materials. In particular, we study the formation of unconventional and/or high temperature superconducting states in the vicinity of quantum phase transitions, although in the course of characterizing new materials, other phenomena are also investigated.

Publications

  1. Superconductivity of barium-VI synthesized via compression at low temperatures D. E. Jackson, D. VanGennep, Y. K. Vohra, S. T. Weir, and J. J. Hamlin
    arXiv:1707.05860, submitted to PRB, July 2017
  1. Channel Morphology and Contact Barrier Engineering in Carbon Nanotube Enabled Vertical Field Effect Transistors by Channel Co-Deposition N. Zhao, B. Liu, M. A. McCarthy, D. VanGennep, X. Chen, R. Jayaraman, J. Hou, J. J. Hamlin, and A. G. Rinzler
    Submitted to ACS Applied Materials and Interfaces, June 2017
  1. Influence of Pressure on the Magnetic Response of the Low-Dimensional Quantum Magnet Cu(H2O)2(C2H8N2)SO4
    M. K. Peprah, D. VanGennep, B. D. Blasiola, P. A. Quintero, R. Tarasenko, J. S. Xia, J. J. Hamlin, M. W. Meisel, and A. Orendáčová
    Acta Physica Polenica A 131, 901 (2017)
  1. Evolution of the Fermi surface of BiTeCl with pressure
    D. VanGennep, D. E. Jackson, D. Graf, H. Berger, and J. J. Hamlin
    J. Phys.: Condens. Matter 29, 295702 (2017)
  1. Pressure-induced superconductivity in the giant Rashba system BiTeI
    D. VanGennep, A. Linscheid, D. E. Jackson, S. T. Weir, Y. K. Vohra, H. Berger, G. R. Stewart, R. G. Hennig, P. J. Hirschfeld, J. J. Hamlin
    J. Phys.: Condens. Matter Letters 29, 09LT02 (2017)
  1. Pressure-tuning of the photomagnetic response of heterostructured CoFe@ CrCr-PBA core@ shell nanoparticles
    M. K. Peprah, D. VanGennep, P. A. Quintero, O. N. Risset, T. V. Brinzari, C. H. Li, M. F. Dumont, J-s. Xia, J. J. Hamlin, D. R. Talham, M. W. Meisel
    Polyhedron 123, 323 (2017)
  1. Frustrated magnetism in the spin-chain metal Yb2Fe12P7
    R. E. Baumbach, J. J. Hamlin, M. Janoschek, J. Singleton, M. B. Maple
    J. Phys.: Condens. Matter, 28, 046004 (2016)
  1. Superconductivity in the metallic elements at high pressures
    J. J. Hamlin
    Physica C, 514, 59 (2015) - invited review article
  1. Pressure dependence of the charge-density-wave and superconducting states in GdTe3, TbTe3, and DyTe3
    D. A. Zocco, J. J. Hamlin, K. Grube, J. H. Chu, H. H. Kuo, I. R. Fisher, M. B. Maple
    Phys. Rev. B, 91, 205114 (2015)
  1. Persistent non-metallic behavior in Sr2IrO4 and Sr3Ir2O7 at high pressures
    D. A. Zocco, J. J. Hamlin, B. D. White, B. J. Kim, J. R. Jeffries, S. T. Weir, Y. K. Vohra, J. W. Allen
    J. Phys.: Condens. Matter, 25, 255603, (2014)
  1. Pressure-tuning the Fermi level through the Dirac point of giant Rashba semiconductor BiTeI
    D. VanGennep, S. Maiti, D. Graf, S. W. Tozer, C. Martin, H. Berger, D. L. Maslov, and J.~J. Hamlin
    J. Phys.: Condens. Matter (Fast Track Communication), 26, 342202, (2014)
  1. Electrical resistivity of single crystals of LaFeAsO under applied pressure
    C. A. McElroy, J. J. Hamlin, B. D. White, S. T. Weir, Y. K. Vohra, and M. B. Maple
    Phys. Rev. B, 90, 125134, (2014)
  1. Pressure-induced superconductivity in LaFeAsO: The role of anionic height and magnetic ordering
    R. S. Kumar, J. J. Hamlin, M. B. Maple, Y. Zhang, C. Chen, J. Baker, A. L. Cornelius, Y. Zhao, Y. Xiao, S. Sinogeikin, and P. Chow
    Applied Physics Letters, 105, 251902, (2014)
  1. Crossover between Fermi liquid and non-Fermi liquid behavior in the non-centrosymmetric compound Yb2Ni12P7
    S. Jang, B. D. White, P. C. Ho, N. Kanchanavatee, M. Janoschek, J. J. Hamlin, and M. B. Maple
    J. Phys.: Condens. Matter 26, 425601, (2014)
  1. Probing the superconductivity of PrPt4Ge12 through Ce substitution
    K. Huang, L. Shu, I. K. Lum, B. D. White, M. Janoschek, D. Yazici, J. J. Hamlin, D. A. Zocco, P.-C. Ho, R. E. Baumbach, M. B. Maple
    Phys. Rev. B 89, 035145 (2014)
  1. Tuning the band gap of PbCrO4 through high-​pressure. Evidence of wide-​to-​narrow semiconductor transitions
    D. Errandonea, E. Bandiello, A. Segura, J. J. Hamlin, M. B. Maple, P. Rodriguez-Hernandez, A. Munoz
    J. Alloys Compd. 587, 14 (2014)
  1. Magnetotransport properties of single-​crystalline LaFeAsO
    C. A. McElroy, J. J. Hamlin, B. D. White, M. A. McGuire, B. C. Sales, M. B. Maple
    Phys. Rev. B 88, 134513 (2013)
  1. Pressure-Induced Unconventional Superconducting Phase in the Topological Insulator Bi2Se3
    K. Kirshenbaum, P. S. Syers, A. P. Hope, N. P. Butch, J. R. Jeffries, S. T. Weir, J. J. Hamlin, M. B. Maple, Y. K. Vohra, J. Paglione
    Phys. Rev. Lett. 111, 087001 (2013)
  1. Ferromagnetic quantum critical point in UCo1-xFexGe
    K. Huang, J. J. Hamlin, R. E. Baumbach, M. Janoschek, N. Kanchanavatee, D. A. Zocco, F. Ronning, and M. B. Maple
    Phys. Rev. B 87, 054513 (2013)
  1. Dependence of the superconducting transition temperature of the filled skutterudite compound PrPt4Ge12 on hydrostatic pressures
    N. Foroozani, J. J. Hamlin, J. S. Schilling, R. E. Baumbach, I. K. Lum, L. Shu, K. Huang, and M. B. Maple
    Physica C 485, 160 (2013)
  1. Thermoelectric Properties of Correlated Electron Systems Ln3Pt4Ge6 and LnPt4Ge12 (Ln = Ce, Pr) and Non-centrosymmetric X2T12P7 (X = Yb, Hf and T = Fe, Co)
    B. D. White, M. Janoschek, N. Kanchanavatee, K. Huang, L. Shu, S. Jang, D. Y. Tutun, J. J. Hamlin, I. K. Lum, R. E. Baumbach, M. B. Maple
    New Materials for Thermoelectric Applications: Theory and Experiment NATO Science for Peace and Security Series B: Physics and Biophysics pp 31-43 (2013)
  1. Intrinsic dependence of Tc on hydrostatic (He-gas) pressure for superconducting LaFePO, PrFePO, and NdFePO single crystals
    N. J. Hillier, N. Foroozani, D. A. Zocco, J. J. Hamlin, R. E. Baumbach, I. K. Lum, M. B. Maple, and J. S. Schilling
    Phys. Rev. B 86, 214517 (2012)
  1. Electronic, magnetic, and electric transport properties of Ce3Rh4Sn13 and Ce3Co4Sn13: A comparative study
    A. Slebarski, B. D. White, M. Fijalkowski, J. Goraus, J. J. Hamlin, and M. B. Maple
    Phys. Rev. B 86, 205113 (2012)
  1. Insensitivity of the pressure dependences of characteristic energy scales in Ce1-xRxCoIn5 (R = Yb, Y, Gd) to the electronic configuration of the rare-earth ion
    B. D. White, J. J. Hamlin, K. Huang, L. Shu, I. K. Lum, R. E. Baumbach, M. Janoschek, and M. B. Maple
    Phys. Rev. B 86, 100502(R) (2012), (Editor's Suggestion)
  1. High pressure transport studies of the LiFeAs analogs CuFeTe2 and Fe2As
    D. A. Zocco, D. Y. Tutun, J. J. Hamlin, J. R. Jeffries, S. T. Weir, Y. K. Vohra, and M. B. Maple
    SUST 25, 84018 (2012)
  1. Superconducting and magnetic anisotropy of LnFePO (Ln = La, Pr, and Nd) single crystals
    R. E. Baumbach, J. J. Hamlin, P.-C. Ho, I. K. Lum, M. B. Maple
    Phys. Rev. B 85, 104526 (2012)
  1. Superconductivity, spin and charge order and quantum criticality in correlated electron materials
    M. B. Maple, J. J. Hamlin, D. A. Zocco, M. Janoschek, R. E. Baumbach, B. D. White, I. R. Fisher, J.-H. Chu
    EPJ Web of Conferences, 23, 00012 (2012)
  1. Transport, magnetic, and thermal properties of non-centrosymmetric Yb2Co12P7
    J. J. Hamlin, M. Janoschek, R. E. Baumbach, B. D. White, and M. B. Maple
    Phil. Mag. 92, 647 (2012)
  1. High pressure transport properties of the topological insulator Bi2Se3
    J. J. Hamlin, J. R. Jeffries, N. P. Butch, P. Syers, D. A. Zocco, S. T. Weir, Y. K. Vohra, J. Paglione, M. B. Maple
    J. Phys.: Condens. Matter 24, 035602 (2012)
  1. Two-fold enhancement of the ``hidden order''/large moment antiferromagnetic phase boundary in the URu2-xFexSi2 N. Kanchanavatee, M. Janoschek, R. E. Baumbach, J. J. Hamlin, D. A. Zocco, K. Huang, and M. B. Maple
    Phys. Rev. B 84, 245122 (2011)
  1. Low-temperature electrical resistivity of praseodymium at pressures up to 120 GPa
    J. J. Hamlin, J. R. Jeffries, G. Samudrala, Y. K. Vohra, S. T. Weir, D. A. Zocco, and M. B. Maple
    Phys. Rev. B 84, 033101 (2011)
  1. Correlated Electron State in Ce1-xYbxCoIn5 Stabilized by Cooperative Valence Fluctuations
    L. Shu, R. E. Baumbach, M. Janoschek, E. Gonzales, K. Huang, T. A. Sayles, J. Paglione, J. O'Brien, J. J. Hamlin, D. A. Zocco, P.-C. Ho, C. A. McElroy, and M. B. Maple
    Phys. Rev. Lett. 106, 156403 (2011)
  1. Search for pressure induced superconductivity in CeFeAsO and CeFePO iron pnictides
    D. A. Zocco, R. E. Baumbach, J. J. Hamlin, M. Janoschek, I. K. Lum, M. A. McGuire, A. S. Sefat, B. C. Sales, R. Jin, D. Mandrus, J. R. Jeffries, Y. K. Vohra, S. T. Weir, and M. B. Maple
    Phys. Rev. B 83, 094528 (2011)
  1. Magnetic, thermal, and transport properties of the actinide based noncentrosymmetric compounds Th2Fe12P7 and U2Fe12P7
    R. E. Baumbach, J. J. Hamlin, M. Janoschek, I. K. Lum, and M. B. Maple
    J. Phys.: Condens. Matter 23, 094222 (2011)
  1. The noncentrosymmetric heavy fermion ferromagnet Sm2Fe12P7
    M. Janoschek, R. E. Baumbach, J. J. Hamlin, I. K. Lum, and M. B. Maple
    J. Phys.: Condens. Matter 23, 094221 (2011)
  1. Evolution of magnetic and superconducting states in UCoGe with Fe and Ni Substitution
    J. J. Hamlin, R. E. Baumbach, K. Huang, M. Janoschek, N. Kanchanavatee, D. A. Zocco, and M. B. Maple
    Mater. Res. Soc. Symp. Proc. 1264, Z12-04 (2010)
  1. The pressure-temperature phase diagram of URu2Si2 under hydrostatic conditions
    N. P. Butch, J. R. Jeffries, W. J. Evans, S. Chi, J. B. Leão, J. W. Lynn, S. V. Sinogeikin, J. J. Hamlin, D. A. Zocco, and M. B. Maple
    Mater. Res. Soc. Symp. Proc. 1264, Z10-03 (2010)
  1. Pressure-induced superconductivity in europium metal
    M. Debessai, T. Matsuoka, J. J. Hamlin, W. Bi, Y. Meng, K. Shimizu, and J. S. Schilling
    J. Phys. Conf. Ser. 215, 012034 (2010)

  2. Unconventional T-H phase diagram in the noncentrosymmetric compound Yb2Fe12P7
    R. E. Baumbach, J. J. Hamlin, L. Shu, D. A. Zocco, J. R. O'Brien, P.-C. Ho, and M. B. Maple
    Phys. Rev. Lett. 105, 106403 (2010)

  3. Non-Fermi liquid regimes and superconductivity in the low temperature phase diagrams of strongly correlated d- and f-electron materials
    M. B. Maple, R. E. Baumbach, N. P. Butch, J. J. Hamlin, and M. Janoschek
    J. Low Temp. Phys. 161, 4 (2010)

  4. Superconductivity for CaC6 to 32 GPa hydrostatic pressure
    M. Debessai, J. J. Hamlin, J. S. Schilling, D. Rosenmann, D. G. Hinks, and H. Claus
    Phys. Rev. B 82, 132502 (2010)

  5. New correlated electron physics from new materials
    M. B. Maple, R. E. Baumbach. J. J. Hamlin, D. A. Zocco, B. J. Taylor, N. P. Butch, J. R. Jeffries, S. T. Weir, B. C. Sales, D. Mandrus, M. A. McGuire, A. S. Sefat, R. Jin, Y. K. Vohra, J. -H. Chu, and I. R. Fisher
    Physica B 404, 2924 (2009)

  6. Strongly correlated electron phenomena in the filled skutterudites
    M. B. Maple, R. E. Baumbach, J. J. Hamlin, P.-C. Ho, L. Shu, D. E. MacLaughlin, Z. Henkie, R. Wawryk, T. Cichorek, and A. Pietraszko
    Properties and applications of thermoelectric materials. Nato science for peace and security series, Springer. V. Zlatic and A. C. Hewson eds. (2009)

  7. Electronic correlations in the iron pnictides
    M. M. Qazilbash, J. J. Hamlin, R. E. Baumbach, L. Zhang, D. J. Singh, M. B. Maple, and D. N. Basov
    Nature Phys. 5, 647 (2009)

  8. Pressure-induced superconducting state of europium metal at low temperatures
    M. Debessai, T. Matsuoka, J. J. Hamlin, J. S. Schilling, and K. Shimizu
    Phys. Rev. Lett. 102, 197002 (2009)

  9. High-pressure, transport, and thermodynamic properties of CeTe3
    D. A. Zocco, J. J. Hamlin, T. A. Sayles, M. B. Maple, J. -H. Chu, and I. R. Fisher
    Phys. Rev. B 79, 134428 (2009)

  10. Superconductivity in LnFePO (Ln = La, Pr, and Nd) single crystals
    R. E. Baumbach, J. J. Hamlin, L. Shu, D. A. Zocco, N. M. Crisosto, and M. B. Maple
    New J. Phys. 11, 025018 (2009)

  11. Pressure induced superconducting phase in the charge density wave compound terbium tritelluride
    J. J. Hamlin, D. A. Zocco, T. A. Sayles, M. B. Maple, J. -H. Chu, and I. R. Fisher
    Phys. Rev. Lett. 102, 177002 (2009)

  12. Superconductivity under high pressure in the binary compound CaLi2
    M. Debessai, T. Matsuoka, J. J. Hamlin, A. K. Gangopadhyay, J. S. Schilling, K. Shimizu, and Y. Ohishi
    Phys. Rev. B 78, 214517 (2008)

  13. Recent studies in superconductivity at extreme pressures
    J. S. Schilling and J. J. Hamlin
    J. Phys. Conf. Ser. 121, 052006 (2008)

  14. Superconductivity in single crystals of LaFePO
    J. J. Hamlin, R. E. Baumbach, D. A. Zocco, T. A. Sayles, and M. B. Maple
    J. Phys.: Condens. Matter 20, 365220 (2008)

  15. Effect of pressure on the superconducting critical temperature of La[O0.89F0.11]FeAs and Ce[O0.88F0.12]FeAs
    D. A. Zocco, J. J. Hamlin, R. E. Baumbach, M. B. Maple, M. A. McGuire, A. S. Sefat, B. C. Sales, R. Jin, D. Mandrus, J. R. Jeffries, S. T. Weir, and Y. K. Vohra
    Physica C 468, 2229 (2008)

  16. Comparison of the pressure dependences of Tc in the trivalent d-electron superconductors Sc, Y, La, and Lu up to megabar pressures
    M. Debessai, J. J. Hamlin, and J. S. Schilling
    Phys. Rev. B 78, 064519 (2008)

  17. Pressure induced superconductivity in CaLi2
    T. Matsuoka, M. Debessai, J. J. Hamlin, A. K. Gangopadhyay, J. S. Schilling, and K. Shimizu.
    Phys. Rev. Lett. 100, 197003 (2008)

  18. Superconductivity studies at extreme pressures
    J. J. Hamlin
    PhD Dissertation, Department of Physics, Washington University in St. Louis (2007)

  19. Pressure-Induced Superconductivity in Sc to 74 GPa
    J. J. Hamlin and J. S. Schilling
    Phys. Rev. B 76, 012505 (2007)

  20. Superconductivity at 20 K in Yttrium Metal at Pressures Exceeding 1 Mbar
    J. J. Hamlin, V. G. Tissen, and J. S. Schilling
    Physica C 451, 82 (2007)

  21. ac susceptibility studies of the weak itinerant ferromagnet SrRuO3 under high pressure to 34 GPa
    J. J. Hamlin, S. Deemyad, J. S. Schilling, M. K. Jacobsen, R. S. Kumar, A. L. Cornelius, G. Cao and J. J. Neumeier
    Phys. Rev. B 76, 014432 (2007)

  22. Superconductivity in Sc Metal and Li(Mg) Alloy under Extreme Pressure
    J. J. Hamlin and J. S. Schilling
    Physica B 403, 1074 (2007)

  23. Superconductivity at 17 K in Yttrium Metal under Nearly Hydrostatic Pressures to 89 GPa
    J. J. Hamlin, V. G. Tissen and J. S. Schilling
    Phys. Rev. B 73, 094522 (2006)

  24. Enhanced Superconducting Properties of Bicrystalline YBa2Cu3Ox and Alkali Metals under Pressure
    T. Tomita, S. Deemyad, J. J. Hamlin, J. S. Schilling, V. G. Tissen, B. W. Veal, L. Chen and H. Claus
    J. Phys. Cond. Mat. 17, S921-8 (2005)

  25. Dependence of the Superconducting Transition Temperature of Single- and Polycrystalline MgB2 on Hydrostatic Pressure
    S. Deemyad, T. Tomita, J. J. Hamlin, B. Beckett, J. S. Schilling, D. G. Hinks, J. D. Jorgensen, S. Lee and S. Tajima
    Physica C 385, 105 (2003)

  26. The Effect of Pressure on the Magnetic Properties of the Molecule-Based Canted Metamagnet Decamethylferrocenium 2,3-Dicyano-1,4-Naphthoquinonide, FeCp*2[DCNQ]
    J. J. Hamlin, B. Beckett, T. Tomita, J. S. Schilling, W. S. Tyree and G. T. Yee
    Polyhedron 22, 2249 (2003)

  27. Hydrostatic Pressure Dependence of the Curie Temperature of [MnR4TPP][TCNE] for R = OC10H21, OC14H29, and F
    C. W. Looney, K. Falk, J. J. Hamlin, T. Tomita, J. S. Schilling, W. Haase and Z. Tomkowicz
    Polyhedron 22, 3339 (2003)

  28. Hydrostatic Pressure Dependence of the Superconducting and Structural Properties of MgB2
    J. S. Schilling, J. D. Jorgensen, D. G. Hinks, S. Deemyad, J. J. Hamlin, C. W. Looney, and T. Tomita
    Studies of High Temperature Superconductors, Vol. 38, edited by A.V. Narlikar (Nova Science Publishers, N.Y., 2001) p.321.

  29. Dependence of Tc on Hydrostatic Pressure in Superconducting MgB2
    T. Tomita, J. J. Hamlin, J. S. Schilling, D. G. Hinks and J. D. Jorgensen
    Phys. Rev. B 64, 092505 (2001)