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Masahiro YAMASHITA

Masahiro YAMASHITA

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Masahiro YAMASHITA

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  1. Electrical Conductivities and Kondo Peak of Single-MoleculeMagnets Masahiro YAMASHITA (Tohoku University)

  2. Outline ○ Conducting Single-Molecule Magnets (SMMs) ○ Memory Device in Pc Multi-Decker Ln SMMs ○ Kondo Peak of Double-Decker Pc2Ln SMMs ○ Field Effect Transistor (FET) of Double-Decker Pc2Ln SMMs ----------------------------------------------------------------------------------------- ○ DMET-CuCl2 : Superconductor ○ DMET-MCl4 : M-I Transition ○ BEDT-TTF Coordinated-CuBr CT Complexes

  3. What is Single-Molecule Magnets ?

  4. Single Molecule Quantum Magnets, SMMs ・Multinuclear nano-cluster metal complexes ・A single molecule behaves like a magnet ・Quantum tunneling effect ・Frequency dependent ac susceptibility ・Cole-Cole plot  ・Heat Capacity Uni-axis anisotropy + Isolated molecules

  5. Quantum Dots: Single Molecule Magnets Mn12O12(O2CR)16(H2O)4: S = 10 Quantum spin tunneling ms = 0 D/kB = |D|S2 D/kB Hendrickson, D. N.; Christou, G. et al, J. Am. Chem. Soc., 1988, 110, 8537. Gatteschi, D. et al, Science, 1994, 265, 1054. ms = +10 ms = -10

  6. Magnets Bulk Magnets Quantum Magnets Increase of the capacity Development of the property @ Clusters Nano-Dots S = 3, 9, 10…. Anisotropy 6.02 x 1023 bit/mol DS2 @ Ising 1-D Chains Nano-Wires Tuning of S and J Large Anisotropy (8J+D)S2 2-D and 3-D Networks 8 x 109 bit (1GB) Molecular memory Quantum computing device

  7. Basic Science ○Multi-FunctionalQuantum Molecular Magnets Applied Science ○One Memory Storage into One Single-MoleculeMagnet ○DNA Quantum Computer ○SMMs and SCMs FET

  8. Multi-Functional Molecule-Based Nano-Magnets Quantum Magnets Conductivity Optics Ferroelectrics Chirality Porosity

  9. DE ・High Tc ・Quantum GMR (S=10, 20, 30) ・Quantum Spintronics SMM SMM e-

  10. Strategy 4+ [Ni(dmit)2]- [Pt(mnt)2]- [Mn4(hmp)6(CH3CN)2(H2O)4](ClO4)4·2CH3CN 2+ Conducting layer SMM Conducting layer [Mn2(5-MeOsaltmen)2(MeCN)2](PF6)2 Segregated structure

  11. Strategy Double-cuboidal tetranuclear manganese cluster [Mn4(hmp)6Br2(H2O)2]Br2 (ST = 9, MnII2MnIII2) G. Christou et al. Inorg. Chem. 2001, 40, 4604. = MnII MnIII MnIII MnII SMM = [Pt(mnt)2]- organic conductor

  12. Synthesis of the Compound constructed from Mn4 and [Pt(mnt)2]x- 4+ Mn4 SMM [Mn4(hmp)6(MeCN)2][Pt(mnt)2]4·2(MeCN) (1) L. Lecren, et. al, J. Am. Chem. Soc. 2005, 127, 17353 Electrochemical oxidation Conductor Pt(mnt)2- [Mn4(hmp)6(MeCN)2][Pt(mnt)2]6(2)

  13. Packing Veiw of [Pt(mnt)2]6[Mn4(hmp)6(MeCN)2] a-axis direction c-axis direction b-axis direction

  14. Conductivity of [Mn4(hmp)6(MeCN)2] [ Pt(mnt)2]6 s = 2.2×10-1 S cm-1 (r.t., 4-probe method) Activation energy 136 meV

  15. Conducting SMM Ni(dmit)2- M(saltmen)- dimer SMM [Mn2(5-MeOsaltmen)2(MeCN)2]2+ H. Miyasaka, et. Al., Angew. Chem. Int. Ed., 43, 2801(2004) Molecular Superconductors Based on Metal Dithiolene Complexes R. Kato, Chem. Rev.2004, 104, 5319-5346

  16. Synthesis of [Mn2(5-MeOsaltmen)2(MeCN)2][Ni(dmit)]7·4(MeCN)(3) [TBA][Ni(dmit)] + [Mn2(5-MeOsaltmen)2(MeCN)2]PF6 + TBAPF6 Electrochemical oxidation Formula weight 4280 Temperature / K 100 Crystal system triclinic Space group P-1 a / 12.0675 b / 12.1753 c /26.5789 Å a / 88.762 b / 79.746 g / 88.047 V / Å3 3840.03 Z =1 R1 = 0.0613, wR2 = 0.1602 GOF = 0.997 Coexistence of [Mn2(5-MeOsaltmen)2]2+ and non-integer [Ni(dmit)2]0.29-

  17. Packing Veiw of [Mn2(5-MeOsaltmen)2(MeCN)2][Ni(dmit)]7·4(MeCN) a-axis direction 2-D conductor (ab plane) c a a-axis direction σ=2.78 S cm-1 c-axis direction σ=0.03 S cm-1 b

  18. DC and AC magnetic susceptibility Jahn-Teller axis

  19. Conductivity of [Mn2(5-MeOsaltmen)2(MeCN)2][Ni(dmit)]7·4(MeCN) s =2.78 S cm-1 (4-probe300 K) a b Activation Energy = 119 eV

  20. New structure of SMM-Conductor; Coordinated {Ni(dmit)2}1- [Mn2(5-MeOsaltmen)2{Ni(dmit)2}2](1) [Mn2(5-Mesaltmen)2{Ni(dmit)2}2](2)

  21. Stair-like column & major distances [Mn2(5-MeOsaltmen)2{Ni(dmit)2}2](1) Conductivity 1; 7 x 10-4 S cm-1(r.t.) 2; 1 x 10-4 S cm-1(r.t.) Activation Energy 1; 182 meV 2; 292 meV [Mn2(5-Mesaltmen)2{Ni(dmit)2}2](2)

  22. Magnetism (DC) · Ideal out-of-plane dimer model J > 0 (SMM) · out-of-plane dimer model J > 0 ·intra-dimer ferromagnetic interaction · out-of-plane dimer model J < 0 ·intra-dimer antiferromagnetic interaction 3pp orbital Orthogonal Overlap Ferromag. Int. Antiferro. Int. Unpaired-electron occupying dz2 orbital [Mn2(5-MeOsaltmen)2{Ni(dmit)2}2](1) [Mn2(5-Mesaltmen)2{Ni(dmit)2}2](2)

  23. Magnetism (AC) Surpressed point (1500 Oe) [Mn2(5-MeOsaltmen)2{Ni(dmit)2}2](1) AC measurement under various field SMM property Deff/kB = 11.4 K (1500 Oe) t0 = 8.2 x 10-7 s Transport property ・s = 7 x 10-4 S cm-1(r.t.) ・Activation energy 119 meV Arrhenius plot ・Semiconductive New type SMM-Conductor: [Ni(dmit)2]1- moiety mediate magnetic interaction and conductivity

  24. Photo-induced Insulator to metal transition in 1D Ni complex Mott insulator →Metal [Ni(chxn)2Br]Br2 Insulator (before excitation) Ni Br N Drude metal C 2 ps Insulator b pz ( Br) dz2 (Ni) J=3000K Iwai et al. Phys. Rev. Lett. 057401(2003).

  25. Ultrafast optical responses in Molecular magnet Photo excitation of charge [Mn2(5-Rsaltmen)2(L)2]2+ 1D electronic system (Mott insulator) Molecular magnet Ni(dmit)2 1.55 m Interaction between 1D electronic system and molecular magnet E // 1D Axis (Charge gap) i) Photo-induced insulator Metal transition → mid-IR pump-probe spectroscopy σ [Ω-1 cm-1] ii) Photo-modulation of magnetic property  → pump-probe (Kerr rotation) E ⊥1D Axis

  26. Photo-induced I-M transition in Molecular magnet Photo excitation of charge →metallization of the Mott insulator 1D electronic system (Mott insulator) ps Molecular magnet pump 0.1 ps 0.15 mJ/cm2 Ultarfast response decay  1ps

  27. Ultrafast control of magnetic property of molecular magnet Photo excitation of charge →change of the spin state ? 1D electronic system (Mott insulator) ps Molecular magnet Sample /2 B polarlizar Pump Probe balanced detection of  (Kerr rotation angle) response of  → M

  28. Basic Science ○Multi-FunctionalQuantum Molecular Magnets Applied Science ○One Memory Storage into One Single-MoleculeMagnet ○DNA Quantum Computer ○SMMs and SCMs FET

  29. H High Spin "down" High Spin "down" Magnetic Tip Surface ≈ 10 nm The dream …

  30. H High Spin "down" High Spin "down" Magnetic Tip Surface ≈ 10 nm

  31. H High Spin "down" Magnetic Tip Surface ≈ 10 nm The dream … HSM «up» … information storage at the molecular level !

  32. H High Spin "down" Surface ≈ 10 nm Nanosciences … HSM «up» … a challenge for chemists and friends …

  33. Phase lag phenomena for (TBA)[TbIIIPc2] (PcH2 = Phthalocyanine) Blue : Diluted with YIII. (TbIII : YIII = 1:4) Red : (TBA)[TbIIIPc2] (TBA)+[TbIIIPc2]- shows maximum at 40 K in cM” at 1kHz AC magnetic field. N. Ishikawa, M. Sugita, T. Ishikawa, S. Koshihara, and Y. Kaizu, J. Am. Chem. Soc.,2003,125, 8694-8695.

  34. Upward temperature shift of the phase lag phenomena by ligand oxidation. [TbIIIPc2]-1 Anionic complex [TbIIIPc2]0 Neutral complex Oxidation upwards the temperature region for phase lag phenomenon from 40 to 50 K. N. Ishikawa, M. Sugita, N. Tanaka, T. Ishikawa, S. Koshihara, and Y. Kaizu, Inorg Chem., 2004, 43, 5498 - 5500.

  35. Change of SMM Properties from Anions to Neutral [TbPc2]-TBA+ Potential Barrier:D= 230 cm-1 Relaxation Time:t0 = 2.0 × 10-8s Blocking Temperature:TB = 40 K [TbPc2]0 Potential Barrier:D= 410 cm-1 Relaxation Time:t0 = 1.5 × 10-9s Brocking Temperature:TB = 50 K

  36. SP-STM tip In-Put/Out-Put spin Au Surface 3-D Strategy Single-Molecule Memory of SMM TbPc2 ★Spin-Polarized STM (↑/↓) =  In-Put/ Out-Put Single-Molecule = 1bit 0-D Fabrication Direct Access to TbPc2 SMM by SpinーPolarized STM Huge Memory Storage

  37. 0.4 nm 1.6 nm Crystal Structutres (Rigaku CCD Saturn70 at 93 K) DyPc2 TbPc2 YPc2 41.4o ● Crystallization:CHCl3/HexDark Green Needles● orthorhombic, P212121 ●Molecular Size: diamiter1.6 nm ×height:0.4 nm  ●Twisted Angles: 41.4o

  38. STM of [Pc2TbIII]at room temperature

  39. STM image for [TbPc2]0at 4.8 K STM image of [TbPc2]0isolated molecules on Au(111) surface Observation LUMO of [TbPc2]0

  40. 分子中心でSTS 8 STS(Scanning Tunneling Spectroscopy): TbPc2/ Au(111) 5×5 nm STM像 ★ TbPc2:Near the Fermi level (V = 0 V)⇒KONDO peak KONDO effect:The Coupling with Magnetic Impurities and Conducting Electrons KONDO Temperature (TK) ≈ 80 K (FWHM:7 meV) kBTK: Binding Energy ≈ 80 K Measure Points center → outside :Sharpe Sample bias Magnetic Impurities: Tb3+ (S = 3) and p-Electron (S = 1/2) ※ Metal Center Change → Dy3+(S = 5/2) and Y3+(S = 0)

  41. Structures of Tb-multiple-deckerPc Compounds Double-decker Triple-decker Quadruple-decker ・blue (solution) ・black crystal ・SMM(TB = 24 K) ・green (solution) ・black crystal ・SMM(TB = 24 K) ・blue (solution) ・black crystal ・SMM(TB = 24 K)

  42. 32o ~0.7 nm ~2.4 nm Crystal structure of Tb2Pc3 (Rigaku CCD Saturn70 at 93 K) triclinic, P-1, black a = 1.31648(11) nm, b = 1.78266(17) nm, c = 2.06226(19) nm, a = 107.2150(10)o, b = 90.5010(10)o, g = 100.8480(10)o V = 4.5296(7) nm3, Z = 1, R1 = 0.0465, wR2 (all) = 0.1337 ■Recrystallization:CHCl3/EtOH ■ Space group:triclinic, P-1 ■ molecular size:2.4 nm ×0.7 nm ■ stacking angle between two Pc: 32o ■Tb・・・Tb: 0.352 nm

  43. MagneticBehaviors of Tb-multiple-deckerPc Complexes Magnetization under Magnetic Field Magnetic Susceptibilities Tb3+×3 Increase Tb3+×2 Tb3+×1 Tb3+×1 Tb3+×2 Tb3+×3 cmTIncrease cmT/cm3 K mol-1 Ms/NmB Tb3+(1 mol) 11.82 Double-decker~10 Triple-decker~20 Quadruple-decker~30 Tb3+(1 mol) 9(sat.) Double-decker4.5 Triple-decker9.8 Quadruple-decker13.5

  44. AC Magnetic Susceptibilities of Multiple-DeckerTbComplexes Triple-decker Double-decker Quadruple-decker TB=24K TB=24K TB=24K

  45. Basic Science ○Multi-FunctionalQuantum Molecular Magnets Applied Science ○One Memory Storage into One Single-MoleculeMagnet ○SMMsand SCMs FET ○DNA Quantum Computer

  46. Quantum Field Effect Transistor (FET) [Pc2Tb] Carbon paste Schematic draw of FET device used in the present measurement

  47. p-Type n-Type

  48. p-Type