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Inhomogeneous electronic states in superconductors (Chapelier, Ioffe) How to disentangle the unavoidable atomic level inhomogeneity of real materials from.

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Presentation on theme: "Inhomogeneous electronic states in superconductors (Chapelier, Ioffe) How to disentangle the unavoidable atomic level inhomogeneity of real materials from."— Presentation transcript:

1 Inhomogeneous electronic states in superconductors (Chapelier, Ioffe) How to disentangle the unavoidable atomic level inhomogeneity of real materials from the electronic inhomogeneity discussion-session

2 Maud Vinet Walter Escoffier Benjamin Sacépé Thomas Dubouchet Charlène Tonnoir Claude Chapelier CEA INAC-SPSMS-LaTEQS, Grenoble Very Low Temperature STM: a powerful probe for inhomogeneous superconducting states (tutorial)

3 Very Low Temperature STM: a powerful probe for inhomogeneous superconducting states (tutorial) I.STM/STS and usual inhomogeneous superconducting states II.Highly disordered superconductors III.Discussion

4 Coarse approach motor Coarse positioning X-Y table Sample holder Tip Piezo tube 10 cm Scanning Tunneling Microscopy Michael Schmid, TU Wien

5 P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) Michael Schmid, TU Wien NbSe 2 Scanning Tunneling Microscopy

6 P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) D. Roditchev’s group, Michael Schmid, TU Wien NbSe 2 Scanning Tunneling Microscopy

7 Scanning Tunneling Spectroscopy P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) I V dI/dV NbSe 2 D. Roditchev’s group,

8 Scanning Tunneling Spectroscopy P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) I V dI/dV NbSe 2 D. Roditchev’s group, H. Hess et al., Physica B 169, 422 (1991)

9 I V dI/dV Scanning Tunneling Spectroscopy P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) NbSe 2 D. Roditchev’s group, H. Hess et al., Physica B 169, 422 (1991)

10 I V dI/dV Scanning Tunneling Spectroscopy P.Mallet et al., J. Vac. Sci. Technol. B 14, 1070 (1996) NbSe 2 D. Roditchev’s group, I. Guillamon et al., Phys. Rev.B 77, (2008)

11 Vortex NbSe 2 Sachdev & Zhang, Science

12 Vortex H. Hess et al., Phys. Rev. Lett.. 62, 214 (1989) NbSe 2

13 Vortex H. Hess et al., Phys. Rev. Lett.. 62, 214 (1989) NbSe 2

14 Vortex NbSe 2 H. Hess et al., Physica B 169, 422 (1991)

15 Vortex H. Hess et al., Physica B 169, 422 (1991) Ch. Renner et al., Phys. Rev. Lett. (1991) Nb 1-x Ta x Se 2

16 Vortex J.E. Hoffman., Science 295, 466 (2002) Bi 2 Sr 2 CaCu 2 O 8+ 

17 Hybrid nanostructures N. Moussy et al., Europhys. Lett. 55, 861 (2001) M. Vinet et al., Phys. Rev. B 63, (2001) H. Le Sueur et al., Phys. Rev. Lett. 100, (2008)

18 Very Low Temperature STM: a powerful probe for inhomogeneous superconducting states (tutorial) I.STM/STS and usual inhomogeneous superconducting states II.Highly disordered superconductors III.Discussion

19 Superconductor-Insulator Transition Granular systemsHomogeneously disordered materials H.M. Jaeger, et al., Phys. Rev. B 34, (1986) D.B. Haviland, et al., Phys. Rev. Lett. 62, 2180 (1989) Gallium Bismuth

20 Superconductor-Insulator Transition TiN  Reactive sputter deposition of TiN films Homogeneously disordered ? N. Hadaceket al., Phys. Rev. B 69, (2004) 100 nm 10 nm

21 Superconductor-Insulator Transition TiN  100 nm 10 nm T (K) R (Ohms) Reactive sputter deposition of TiN films Granular ? Homogeneously disordered ? N. Hadaceket al., Phys. Rev. B 69, (2004)

22 Superconductor-Insulator Transition TiN  T (K) R (Ohms) Reactive sputter deposition of TiN films Granular ? Homogeneously disordered ? N. Hadaceket al., Phys. Rev. B 69, (2004) ≈ 80 × 80 × 2 nm ≈ 400 × 400 × 3 nm W. Escoffier et al.,Phys. Rev. Lett. 93, (2004) 100 nm 10 nm

23 Superconductor-Insulator Transition TiN  Reactive sputter deposition of TiN films Homogeneously disordered ? N. Hadaceket al., Phys. Rev. B 69, (2004) ≈ 80 × 80 × 2 nm ≈ 400 × 400 × 3 nm W. Escoffier et al.,Phys. Rev. Lett. 93, (2004) 100 nm 10 nm

24 M. Baklanov and A. Satta (IMEC) Superconductor-Insulator Transition TiN Atomic layer deposition of 5 nm thick TiN films

25 Increasing disorder Superconductor-Insulator transition Sacépé et al., Phys. Rev. Lett. 101, (2008) TiN

26 Superconductor-Insulator transition TiN λ Sacépé et al., Phys. Rev. Lett. 101, (2008) T c [K]Δ/T c Var. [%] A. Ghosal, M. Randeria, N. Trivedi, Phys. Rev. Lett. 81, 3940, (1998) Phys. Rev. B 65, (2001) M. Ma and P.A. Lee, Phys. Rev. B 32, 5658, (1985) A. Kapitulnik, G. Kotliar, Phys. Rev. Lett. 54, 473, (1985) M. Feigel’man et al., Phys. Rev. Lett. 98, , (2007) M. Feigel’man et al., Ann. Phys. 325, 1390 (2010) M. A. Skvortsov et al., Phys. Rev. Lett. 95,057002, (2005)

27 Pseudogap B. Sacépé, et al., Nature Communications 1:140 (2010)

28 Superconducting fluctuations correction to the DOS Short-lived Cooper pairs above Tc A. Varlamov and V. Dorin, Sov. Phys. JETP 57, 1089, (1983) Pseudogap B. Sacépé, et al., Nature Communications 1:140 (2010)

29 Superconducting fluctuations correction to the DOS Short-lived Cooper pairs above Tc A. Varlamov and V. Dorin, Sov. Phys. JETP 57, 1089, (1983) Pseudogap B. Sacépé, et al., Nature Communications 1:140 (2010) R □ [kΩ] T c (R □ ) [K] T c (DOS) [K] An extreme sensitivity to Tc

30 Very Low Temperature STM: a powerful probe for inhomogeneous superconducting states (tutorial) I.STM/STS and usual inhomogeneous superconducting states II.Highly disordered superconductors III.Discussion How to disentangle the unavoidable atomic level inhomogeneity of real materials from the electronic inhomogeneity ? Which inhomogeneities ? Down to which scale a real material must be considered granular or not ? What is a homogeneously disordered material ? How can we relate global macroscopic behavior (transport) and local signatures (STS) ?

31 Dilution fridge setup

32 Anomalous proximity effect Superconducting granular TiN films d S,N W. Escoffier et al., Phys. Rev. Lett. (2004) ≈ 80 × 80 × 2 nm ≈ 400 × 400 × 3 nm Theory : Zhang & Xiong, Physica C (2006)

33 Anomalous proximity effect Superconducting granular TiN films B. Sacépé (unpublished) 1500 nm x 1500 nm

34 Superconducting fluctuations quantum corrections

35 T c [K] One parameter fit : T c Superconducting fluctuations quantum corrections


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