• Atomic Physics
• Biophysics Theory and Experiment
• Cond Matter Experiment Faculty
  • Robert H. Austin
  • M. Zahid Hasan
  • Nai Phuan Ong
  • Jason Petta
  • Ali Yazdani
  • Sandra Troian (Chem Eng)
  • Daniel C. Tsui (Elec Eng)
  • Paul M. Chaikin (at NYU)

• Condensed Matter Theory
• Cosmology Experiment
• Cosmology Theory
• High Energy Experiment
• High Energy Theory
• Mathematical Physics
• Particle and Nuclear Astrophysics

• Quantitative and Computational Biology
• Cosmology at Princeton
• Lewis-Sigler Institute
• Princeton Center for Theoretical Physics
• Princeton Institute for the Science
  and Technology of Materials

I am interested in scattering based spectroscopic investigations of novel quantum phases of matter realized via topological ordering, strong-interaction or geometrical frustration and their combinations. Quantum Hall phases, correlated superconductors and frustrated magnets have profoundly changed our microscopic understanding of interacting quantum matter. My research is focused on the frontier aspects of these areas of fundamental condensed-matter physics. I am currently interested in the quantum spin Hall phases (Topological Order) in strong spin-orbit coupled materials and topological quantum phase transitions leading to the quantum Hall insulators; superconductivity in strongly correlated triangular lattice materials (Correlated Superconductors) and spin-liquid-like behavior in certain classes of frustrated magnet materials (RVB-type fractionalized phases) in search of direct/unambiguous signatures of electron fractionalization in higher dimensions. Examples of topological ordering of quantum matter include charge quantum Hall effect, novel topological insulators, anti-localization, quantum spin Hall effect, helical surface modes and topological quantum phase transition. Examples of strong-interaction physics include Mott phenomena such as electron fractionalization or competing orders such as CDW vs. superconductivity and examples of geometrical frustration physics include spin-liquids and its competing orders such as dimer phases or bond-frustration. Topological insulators have been proposed as a possible route to quantum computing and related spin-orbit Dirac materials can potentially provide spin currents for spintronics applications. On the other hand, doped Mott insulators on triangular lattices not only exhibit exotic superconductivity but also feature high thermopower figure of merit for applications. Currently, there is no obvious application of spin-liquids but some spin-liquids may exhibit “topological order” and fractionalization which is of interest to me. My recent (2000-present) research work has focused in the following areas: Topological Order in Quantum Hall-like systems: Topological phases. Experimental methods and direct imaging/determination of topological order parameter of the Quantum Spin Hall Phase and inverted spin-orbit insulators. Quantum Hall effect without Landau levels. Ternary and binary alloys of bismuth and related compounds. Doping of a topological Hall surface state. Quantum Hall effect without external magnetic fields. Search for a route to Quantum Computing. (Nature-2008) Novel Dirac materials for spintronics: Dirac physics in non-Graphene systems (graphene has a vanishingly small spin-orbit coupling). Domain wall Fermions, Search for parity anomaly without Fermion doubling. Rashba and Dresselhaus soc field effects etc. Phase transition between a Bloch insulator and the quantum spin Hall insulator. Topological doping of a Dirac spectrum. (Nature-2008) Competition and Co-existence of Superconductivity and CDW phases: Non-nested CDWs, Commensurate CDWs in two dimensions, Excitonic CDW as a competing order to superconductivity, spin-dependent thermoelectricity, Kohn-Overhauser phases, Charge-order and superconductivity: Doped cobaltates, Titanate TMDs and related compounds. (Phys.Rev.Lett.s 2007a,b,c, preprints 2008). Novel phases of Correlated Electrons on Frustrated Lattices: Fermiology and quasiparticle dynamics, Collective charge and spin excitations in strongly interacting quantum electron systems. Mott phenomena, metal-insulator transition, charge-order, superconductivity, high thermopower, spin-dependent thermoelectricity, Order-by-Frustration phenomena, quantum zero modes. Doped cobaltates and related compounds. (Phys.Rev.Lett.s 2006a,b,c, preprints 2008). Collective Charge Modes in doped Mott insulators: X-ray Imaging techniques. Development of high resolution bulk-sensitive momentum-resolved x-ray techniques to probe collective charge excitation modes in doped Mott insulators, Cuprates near AFM/SC transition. Full Brillouin zone imaging in inelastic resonant x-ray scattering demonstrated (Science 2000, Phys.Rev.Lett./Bs 2002-2008). Novel spectroscopic method development: Designs of coherent light based spectroscopic techniques to probe fundamental issues in condensed-matter physics. Measurement of electron-orbit quantization in a strong magnetic field. (2007-). Advanced scattering probes (Synchrotron photons, electrons, neutrons) are used to study order and excitations of correlated electrons in various condensed matter systems. Scattering probes allow one to measure various orders of correlation functions and order parameters and reveal the quantum numbers (energy, momentum or spin) of electrons in crystals which describes the phase (Fermi surface topology, quasiparticle self-energy etc.) or some collective excitations such as magnons, phonons, plasmons or holons/solitons over the entire Brillouin zones (allowing to classify the broken-symmetry phases). Precise experimental measurements of dispersion relations (E vs. k or Q) of these elementary quantum and collective excitation modes provide fundamental insights about the microscopic physics of the complex systems. We use three principal classes of techniques: Inelastic, Elastic, Resonant & Coherent X-ray Scattering (at ALS & APS) Angle-Resolved Photoemission (ARPES) (at ALS, SSRL and SRC) Neutron Scattering with strong magnetic fields (at NIST, ISIS-Oxford) Experiments are performed at national and international laboratories (Argonne, Brookhaven, Lawrence-Berkeley, ESRF/France, SSRL/SLAC, NIST, Spring8/Japan, ISIS/Oxford), as well as at Joseph Henry Labs at Princeton. We are currently developing two novel high resolution (~10-100 meV) state-of-the-art synchrotron X-ray scattering spectrometers - one to work around 1 KeV and another around 100 eV at the Advanced Light Source of LBL (Co-leading the development of MERLIN (at ALS). We are also scientific members of scattering consortia at APS/ANL and LCLS/SLAC. Research Opportunities in the Hasan Lab: Research opportunities exist for highly motivated graduate and undergraduate students. Interested students are encouraged to contact me (mzhasan@princeton.edu.)

S e l e c t e d   P u b l i c a t i o n s:

D. Hsieh, D. Qian, L. Wray, Y. Xia, Y. Hor, R.J. Cava and M.Z. Hasan A Topological Dirac insulator in an unusual quantum spin Hall phase Nature (2008). D. Qian, D. Hsieh, L. Wray, Y.-D. Chuang, A. Fedorov, D. Wu, J.L. Luo, N.L. Wang, L. Viciu, R.J. Cava and M.Z. Hasan Emergence of Fermi Pockets in a New Excitonic CDW Melted Superconductor CuxTiSe2 Physical Review Letters 98, 117007 (2007). G. Li, W.Z. Hu, D. Qian, D. Hsieh, M.Z. Hasan, E. Morosan, R.J. Cava, N.L. Wang Evidence for an Oherhauser phase and semimetal-to-semimetal Charge Density Wave Transition in the parent compound of CuxTiSe2 Physical Review Letters 99, 027404 (2007). D. Qian, L. Wray, D. Hsieh, L. Viciu, R.J. Cava, J.L. Luo, D. Wu, N.L. Wang, and M.Z. Hasan Complete d-Band dispersion relation and small Fermion scale in NaxCoO2 Physical Review Letters 97, 186405 (2006). D. Qian, D. Hsieh, L. Wray, Y.-D. Chuang, A. Fedorov, D. Wu, J.L. Luo, N.L. Wang, L. Viciu, R.J. Cava and M.Z. Hasan Low-lying quasiparticle modes and hidden collective charge instabilities in parent cobaltates superconductors NaxCoO2 Physical Review Letters 96, 216405 (2006). D. Qian, L. Wray, D. Hsieh, A. Kuprin, A. Fedorov, D. Wu, J. L. Luo, N.L. Wang, L. Viciu, R.J. Cava and M.Z. Hasan Quasiparticle’s quantum coherence and dynamics in the vicinity of metal-insulator phase transition in NaxCoO2 Physical Review Letters 96, 046407 (2006). M. Z. Hasan, Y.-D. Chuang, D. Qian, Y.W. Li, Y. Kong, A. Kuprin, A.V. Fedorov, R. Kimmerling, E. Rotenberg, K. Rossnagel, Z. Hussain, H. Koh, N.S. Rogado, M.L. Foo, and R. J. Cava Fermi surface topology and quasiparticle dynamics of host NaxCoO2 investigated by ARPES Physical Review Letters 92, 246402 (2004). J.E. Kohn, I.S. Millett, J. Jacob, et al. Random-coil behavior and the dimensions of chemically unfolded proteins: A view with X-ray forward scattering Proc. of the Nat. Acad. of Sci, 101, 12491 (2004). M.Z. Hasan, P.A. Montano, E.D. Isaacs, Z.X. Shen, S. Sinha, Z. Islam, H. Eisaki, N. Motoyama and S. Uchida Momentum-resolved Charge Modes (Holons) in a Prototype 1-D Mott Insulator Studied by Inelastic X-ray Scattering Physical Review Letters 88, 177403 (2002). M.Z. Hasan, E.D. Isaacs, Z.X. Shen, L.L. Miller, K. Tsutsui, T. Tohyama and S. Maekawa Electronic Structure of Mott Insulators Studied by Inelastic X-ray Scattering Science 288, 1811 (2000). R. Reininger et al. Instrumentation: Beamline & Spectrometer Development: MERLIN — A meV Resolution Beamline at the ALS Am. Inst. of Phys: Conf. Proc. 879, 509 (2007).