Superconductivity, quantum Hall effect, and magnetic field induced spin density waves in (TMTSF)[sub 2]X
A remarkable diversity of phenomena is observed in the quasi-low dimensional organic conductor (TMTSF)[sub 2]PF[sub 6] and other Bechgaard salts. An extensive phase diagram study shows that a single crystal of (TMTSF)[sub 2]PF[sub 6] exhibits metallic, semiconducting, semimetallic, antiferromagnetic, spin density wave (SDW), and superconducting phases as pressure, temperature, and magnetic field are varied. In addition, (TMTSF)[sub 2]PF[sub 6] exhibits a set of unique magnetic Field-Induced Spin Density Wave (FISDW) transitions and is the first bulk material to exhibit Quantum Hall effect (QHE). The phase diagram of (TMTSF)[sub 2]PF[sub 6] shows a good agreement with the [open quotes]standard model[close quotes] of FISDW. The phase diagram shifts nicely with pressure and magnetic field and can be understood as a consequence of changing dimensionality of the system. Under tilted magnetic field, spectacular resonances occur in both the metallic and the FISDW states at the [open quotes]magic[close quotes] angles where the electronic motion becomes commensurate. Another member of the Bechgaard salt (TMTSF)[sub 2]ClO[sub 4] also undergoes FISDW transition. However, it exhibits a more complicated behavior such as oscillatory Hall effect, possible fractional QHE, reentrant phase diagram, and a high field insulating phase. The author has found that it is possible to suppress the anion ordering transition in (TMTSF)[sub 2]ClO[sub 4] by application of pressure greater than 5 kbar. Without anion ordering the ClO[sub 4] salt exhibits FISDW behavior similar to (TMTSF)[sub 2]PF[sub 6]. Below 5 kbar, the system reverts back to the complicated behavior. In the non-superconducting member of Bechgaard salt, (TMTSF)[sub 2]NO[sub 3], presence of low temperature SDW phase but no superconductivity and FISDW suggests importance of electron-electron interaction and questions the present understanding of FISDW.
- Research Organization:
- Princeton Univ., NJ (United States)
- OSTI ID:
- 7273971
- Country of Publication:
- United States
- Language:
- English
Similar Records
Superconductivity and magnetic-field-induced spin-density waves
Anion disorder and two-dimensionality in the superconducting and SDW states of (TMTSF){sub 2}ClO{sub 4}
Related Subjects
360602 -- Other Materials-- Structure & Phase Studies
360607* -- Other Materials-- Superconducting Properties-- (1992-)
CHALCOGENIDES
CHLORINE COMPOUNDS
CHLORINE OXIDES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALL EFFECT
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC SUPERCONDUCTORS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHOSPHORUS COMPOUNDS
PHOSPHORUS FLUORIDES
SELENIUM COMPOUNDS
SUPERCONDUCTORS
TMTSF