Niels Bohr Institute, Nano-Science Center, University of Copenhagen Isaac Newton Institute Workshop, Cambridge 27-30 September 2004 Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods Poul Erik Lindelof Niels Bohr Institute, Nano-Science Center, University of Copenhagen 18-Sep-18 Niels Bohr Institute

Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods Poul Erik Lindelof Niels Bohr Institute, Nano-Science Center, University of Copenhagen Henrik Ingerslev Jørgensen, PhD student Jonas Rahlf Hauptmann, PhD-student Thomas Sand Jespersen, PhD-student Kasper Grove-Rasmussen, Ph.D.-student (p.t. visiting NTT BRL, Japan) Ane Jensen, Dr Jesper Nygård, Dr & collaboration with Andrei Khlobystov, Oxford University 18-Sep-18 Niels Bohr Institute

Field Effect Transistor Behaviour in Single Wall Carbon Nanotubes and Peapods Outline of talk: Importance of contacts, Coulomb blockade, odd-even effects due to spin Zeeman splitting, ESR? Kondo effect Hybrids with GaAs Magnetic contacts Peapods, Periodic modulation Summary Notes may be nice 18-Sep-18 Niels Bohr Institute

3 carbon nanotubes (10,10) (15,0) (12,8) 18-Sep-18 (10,10) (15,0) (12,8) 18-Sep-18 Niels Bohr Institute

TEM of carbon nanotube robe A nanotube (or two?) TEM picture 20 nm 18-Sep-18 Niels Bohr Institute

Assignment by Raman spectra Thomas Sand Jespersen, MSc thesis 18-Sep-18 Niels Bohr Institute

Contact configuration although carbon atoms only! Contact configuration 2-point Electrical Resistance drain Au/Ti contacts Carbon nanotube Silicondioxide (300 nm) Highly doped silicon source gate 18-Sep-18 Niels Bohr Institute

Contacting a SWCNT 10µm 50µm 18-Sep-18 Niels Bohr Institute

SWCNT, metals or semiconductors 18-Sep-18 Niels Bohr Institute

3 examples of Contact resistances G300K = 0.3 e2/h G300K = 1.8 e2/h G300K = 3 e2/h It is ThreeTypesGVg.OPJ, originally made for the Kondo paper Devices: cdot, yin, metallicA T = 1K T = 100mK Theoretical maximum Gmax = 4 e2/h 18-Sep-18 Niels Bohr Institute

Metallic SWCNT, Temperature Dependence P.E. Lindelof, et al., Physica Scripta T02, 22 (2002) 18-Sep-18 Niels Bohr Institute

Odd-Even Additional energies D.H. Cobden and J. Nygård Phys,Rev,Lett. 89, 046803 (2002) 18-Sep-18 Niels Bohr Institute

Bias Spectroscopy, Zeeman splitting P.E. Lindelof , et al., Physica Scripta T02, 22 (2002) 18-Sep-18 Niels Bohr Institute

Wolfgang Pauli and Niels Bohr 1951, looking at a spinning object! 18-Sep-18 Niels Bohr Institute

Kondo bias spectroscopy Q E O D eV J. Nygård et al., Nature 408,342 (2000) 18-Sep-18 Niels Bohr Institute

Kondo temperature a b c J. Nygård et al., Nature 408, 342 (2000) G0 (e2/h) TK (K) a b c Fig 2 abc from modified Fig2FatCompilation.OPJ Fig 2mega meg56Fat1_v2cut.hdf, meg56Fat2_cut.hdf Fig 2 IV white_I-V_and_FWHMs.OPJ J. Nygård et al., Nature 408, 342 (2000) 18-Sep-18 Niels Bohr Institute

Carbon nanotube inside a MBE GaAlAs single crystall = + A. Jensen, J.Hauptmann, J, Nygård, J. Sadowski, P.E. Lindelof, Nano Letters (2004) 18-Sep-18 Niels Bohr Institute

Device fabrication MBE chamber MBE grown substrate: - n-doped GaAs - insulating superlattice barrier - amorphous As cap (protection) Dispersion of single-wall nanotubes from suspension, ambient conditions 18-Sep-18 Niels Bohr Institute

Device fabrication MBE chamber Epitaxal overgrowth with Ga0.95Mn0.05As by MBE at 250 C Result: nanotubes incorporated in GaAs sandwich Reloaded in the MBE chamber Desorption of As cap at 400 C, leaving the nanotubes on the clean GaAs crystal surface 18-Sep-18 Niels Bohr Institute

Mesa, Trench etch, SWCNTs Trench and SWCNT 18-Sep-18 Niels Bohr Institute

Device architecture a) b) 7 5 4 6 3 2 1 Au/Zn (Ga,Mn)As SWNT Cr/Au x100 2 AlAs 1 GaAs 18-Sep-18 Niels Bohr Institute

Configurations in various magnetic fields 18-Sep-18 Niels Bohr Institute

AFM scan of SWCNT between MBE grown GaAs electrodes Single wall carbon nanotube GaAs The trench is 0.5 µm wide 18-Sep-18 Niels Bohr Institute

G(Vg,B) for GaMnAs-SWCNT-GaMnAs 18-Sep-18 Niels Bohr Institute

G(Vsd,B,T) for GaMnAs-SWCNT-GaMnAs 18-Sep-18 Niels Bohr Institute

Magnetoresistance of GaMnAs-SWCNT-Au 18-Sep-18 Niels Bohr Institute

Juliere’s model G(++)~n(1,+)n(2,+)+n(1,-)n(2,-) P(1)=[n(1,+)-n(1,-)]/[n(1,+)+n(1,-)] DG/G=[G(++)-G(+ -)]/G(++) =2P(1)P(2)/[1+P(1)P(2)] >0 Negative magnetoresistance 18-Sep-18 Niels Bohr Institute

Tunnelling into two domains (Streda, unpublished) Tt T(1,+) T(2,-)= T(2,-) T(1,+)=pT1, T(1,-)=(1-p)T1, T(2,+)=T(2,-)=T2 G(p=1)=G(+)+G(-)=T1TtT2/[Tt(T1+T2)+2T1T2] G(p=1)-G(p=½)= -G(p=1)[T1/T2 + 2T1/Tt] magnetoresistance>0 18-Sep-18 Niels Bohr Institute

C-60@SWCNT Peapod K. Haldrup, A.N. Khlobystov et al. 18-Sep-18 Niels Bohr Institute

Raman spectra a) SWCNT b) SWCNT - through treatment c) C-60@SWCNT Peapod 18-Sep-18 Niels Bohr Institute

Peapod Conductance vs. Vg 18-Sep-18 Niels Bohr Institute

G(290) vs. power law exponent. C-60@SWCNT (O) & SWCNT (l) Haldrup, Khlobystov et al., To be published 18-Sep-18 Niels Bohr Institute

Nanometer periodic modulation of potential along SWCNT Thomas Sand Jespersen, Poul Erik Lindelof, unpublished 18-Sep-18 Niels Bohr Institute

MBE growth of SL with guiding structures. Cleaved Edge Overgrowth 18-Sep-18 Niels Bohr Institute

AFM picture of cleaved and etched surface 18-Sep-18 Niels Bohr Institute

AFM study of 30 nm period superlattice on the cleaved edge 18-Sep-18 Niels Bohr Institute

Carbon nanotube decoration of CEO SL surface 18-Sep-18 Niels Bohr Institute

SWCNT superlattice Raman spectrum. No data for the combination yet. 18-Sep-18 Niels Bohr Institute

Summary The contact resistance to metallic carbon nanotubes, Temperature dependence of electrical conductance Odd-even Coulomb blockade conductance peaks Zeeman splitting (g=2) Spin ½ co-tunneling (Kondo effect) GaAs-CNT hybrids, magnetic contacts Peapods, CEO periodic modulation 18-Sep-18 Niels Bohr Institute

Movie of ”spinning object” 18-Sep-18 Niels Bohr Institute

The ”spinning object” in action 18-Sep-18 Niels Bohr Institute