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Quantum M atter R esearch under E xtreme Physical C onditions Outlook for 2006-2007 in Korea

Sep. 27, 2006. Quantum M atter R esearch under E xtreme Physical C onditions Outlook for 2006-2007 in Korea. Kee Hoon Kim School of Physics and Astronomy & Center for Strongly Correlated Material Research eXtreme Multifunctional Physics Laboratory (XMPL),

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Quantum M atter R esearch under E xtreme Physical C onditions Outlook for 2006-2007 in Korea

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  1. Sep. 27, 2006 Quantum Matter Research under Extreme PhysicalConditions Outlook for 2006-2007 in Korea Kee Hoon Kim School of Physics and Astronomy & Center for Strongly Correlated Material Research eXtreme Multifunctional Physics Laboratory (XMPL), Seoul National University, South Korea

  2. Quantum Matter Group (Cavendish Lab.) SNU (XMPL) Kee Hoon Kim (Exp.) Peter Littlewood (Theory) Christoph Bergemann (Exp.) Peter Mann S. S. Saxena Stephen Rowley G. G. Lonzarich Post-doc: Peter Mann Deepshikha Jaiswal Raj Sankar Ph D candidates: Yoon Seok Oh Jae Wook Kim So-Young Haam MS students: Sewhan Chun, Ingyu Kim

  3. Quantum Criticality Proposed to Instigate New Phases Including Exotic Superconductivity Non-Fermi Liquids Reasons: 1: fluctuations (e.g. spin fluctuations) present at T = 0 can mediate quasiparticle pairing Pseudogap FL SC AFI rFL=rres+AT2 2: singular density of states (i.e. m*  ) is unstable. Superconductivity very efficient at opening gap and lowering energy AFM FL SC Fundamental questions: can we understand new states of matter including exotic orders like high Tc superconductivity? R. B. Laughlin et al., Adv. Phys.50, 361 (2001).

  4. Quantum Matter Research Agenda Cavendish Quantum Matter Group SNU (XMPL) Clamp cell: 30 kbar P Anvil cell: 150 kbar Exploring correlated electron system under extreme physical conditions Cavendish Correlated Electron Theory Group Dilution Fridge 5 mK Superconducting B up to 21 T B, T

  5. GaFeO3 TbMn2O5 Tools I: Quantum Matter Growth + Crystallography (x) Optical Floating Zone Furnace +Flux Growth Technique (Quantum) Multiferroics RMnO3… Highly frustrated quantum spin system A new correlated Fermion system Pt crucible Polarized Microscope Real time Laue analyses

  6. Tools II: Measurements under High Field up to 100 T (B) 60 T calorimeter 33 T Nanocalorimeter All plastic and silicon; no eddy current !! 100kHz ac tools Synchronous Clock (n x f ) Dual Synthesizer Digitizer Signal Drive ( f ) Phase-sensitive Synchronous Detection

  7. Outstanding problems to be answered • How the phases can be formed near the QCP of a correlated matter? Is the new phase really linked to the QCP? • A QCP can involve the large FS reconstruction? Fermiology vs Hall effects

  8. K. H. Kim et al. PRL 93, 126404 (2004); K. H. Kim PRL 2003

  9. Research Highlight : Hall studies of U(Ru1-xRhx)2Si2 Rh 0 % Rh 4 % Y. S. Oh et al. submitted to PRL RH=rxy/B=-1/ne Results of pulsed field explorations A jump in carrier number (n ~1 el/U) across phase II suggests the FS reconstruction to induce a discontinuous Fermi surface volume change. dHv study at Cavendish lab. is most valuable to this problem

  10. Quantum Magnetism-Ferroelectricity Coupling in Multiferroics Charge GaFeO3 TbMn2O5 Multifunctional Multiferroic materials Spin Orbital Magnetic control Electric control Lattice/photonic control Next generation memory materials with more control ability Very hot emerging research area 2003-2006Nature 5Nature materials 6Science 7PRL 22 New material search+ highly senstive measurements tools: APSFocus Session 2003년1 2004년1 2005년2 2006년4 New multiferroics? ; Fundamental coupling mechanism?; Needs for multiphase space exp. ?

  11. Research Highlight : B-T phase diagram of multiferroics TbMn2O5 Electric polarization map of a multiferroic under high magnetic fields S. Y. Haam et al., to submitted to PRL 9T : PPMS 45T: static field 45T: mid-pulse 60T: short-pulse 100T: short-pulse Multiferroic Xtals Nano-Pillar Composite RMn2O5, RMnO3, RCrO3 PZT:CoNi2Fe4 New high field phase transition Quantum Paraelectric Matter Understanding of electric polarization generation electric polarization dielectric constant PE hysteresis loop Magnetic birefringence Magnetoelectric susceptibility (film and low T study ready

  12. ε(T) of BiMn2O5 at constant magnetic field Careful T sweep of dielectric constant near Bc down to 0.6 K J. W. Kim et al. to be submitted A sign of quantum ferreoelectrics Very similar to the well-known quantum paraelectric behavior of SrTiO3 Can be a new quantum paraelectric achieved with magnetic field tuning?

  13. Outstanding problems to be investigated 1. Can we find a new quantum paraelectrics near the quantum critical point of ferroelectrics or multiferroics? BiMn2O5 case 2. Can we realize new multiferroics ? (eg. SnTe doped with Mn?) Theory + Experiments (Design of materials) 3. Developments of quantum technology to explore challenging measurements Tiny magnetic moment measurement as tuned by electric fields Tiny specific heat measurements under quantum regime to see electronic quantum oscillations or to study phase transition at low T

  14. Research plan, Ag5Pb2O6: a simple superconductor? Peter Mann Recently discovered superconducting below 50mK, Ag5Pb2O6 has a very simple Fermi surface with m*/m~1. Sutherland et al, PRL 96, 097008 (2006) Mann et al, Physica C, M2S Proc. (2006) However, the resistivity is not simple. It has quasi-T2 dependence up to at least room temperature. What is the cause? Phonons? It will be useful to measure C more precisely up to and beyond 400K using the high T heat capacity probe, to confirm saturation to Dulong-Petit value. Plus we need more theory input…! Yonezawa and Maeno, PRB 70, 184523 (2004)

  15. Research plan : Electric Field Induced Magnetic Moment Multiferroic crystal & film Fab. of highly senstive-measurement tool Study on new multiferroic materials and their nanostructure Ba-Hexaferrite, Y3Fe5O12, GaFeO3 Torque magnetometer Ni3B7O12I Switching of P (E~1000V/cm) by 180 deg. with a rotation of M (H~0.1 T) by 90 deg. Search for materials showing magnetic moment variation actuated by electric fields Developments of magnetoelectric device with naopillar and multilayer forms Z P Ms y x Electric field induced magnetization study E-torque magnetometer developments and measurements for multiferroic thin film devices and crystals E-VSM developments and study Magnetoelectric susceptibility measurements for films at low temperatures

  16. Future Research Strategy Nano-calorimeter technique Striction cell fabrications ~10 mK ultralow temperature High pressure measurements 韓 SNU Quantum Matter Search, Growth, and Characterization Pressure cell development (4GPa) Ultralow temp.(mK) calorimetry Quantum Matter & Quantum Phase Transition 英 Cambridge Univ. Torque magnetometer Nanocalorimetry QPT study Quantum Matter Theory + High B & High B 1st year2nd3rd We’re looking forward to being part of the CKC family!

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