- Text
- Magnetic,
- Diagram,
- Pairs,
- Films,
- Insulator,
- Density,
- Electron,
- Superconductor,
- Transition,
- Fermions

Phase Diagram of Electron Systems near the Superconductor ...

ResistivityAssume Mott variable range hopping :R = R 0 exp[− (T 0 /T ) 1/(d+1) ]Increase for increasing field since tail **of** wave function changes from simpleexponential to GaussianDecrease for increasing field B>B BFT since T 0 forbosons is much larger than for fermions.T 0fT 0b≈ n bn fLcbL cf d+2∼LcbL cf 2= O(10 −2 )

Conclusions•! **Phase** diagram depends on dimensionality. In thin films it depends on **the**magnetic field direction.•! In all considered situations **the**re are 4 interplayingphases: Bose Insulator, Fermi Insulator, Metal and **Superconductor**•! Transitions between **the**m are due ei**the**r to paramagnetic depairing orto squeezing **of** Cooper pairs by **the** random potential well in magnetic field•! Negative magnetoresistance appears due to proliferation **of** fermions whichare weakly confined by **the** random field.•! In thick film or bulk **the** phase diagram does not depend on direction **of**magnetic field, however **the** resistivity must be anisotropic.

- Page 1 and 2: Phase diagram of electron systemin
- Page 3: Outline•! Experimental facts•!
- Page 7 and 8: Amorphous films In 2 O 3-xTemperatu
- Page 9 and 10: Superconductor to insulator transit
- Page 11: Disappearance of superconducting is
- Page 15: Model assumptions•! Cooper pairs
- Page 18 and 19: Idea for GNM:CP pairs fill localize
- Page 20 and 21: Simplification Ψ(r) ∼ e −r2 /2
- Page 23: Zero magnetic fieldDensity of well
- Page 26 and 27: Extension to finite magnetic fieldd
- Page 28 and 29: Increase magnetic field such thatµ
- Page 30 and 31: How the density of fermions grows a
- Page 32 and 33: Thin film in perpendicular fielddia
- Page 34: Three dimensional systemψ k (x) =