Are Lebed’s Magic Angles Truly Magic?

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We have performed high-frequency (microwave spectral range) Angle-dependent Magneto- Resistance Oscillation (AMRO) measurements in the low- dimensional organic conductor (TMTSF) 2 ClO 4 . We show that the angles at which AMRO dips are observed depend on the ratio of v/B, where v is the measurement frequency (40 – 150GHz) and B is the magnetic field strength. At v = 0, the data exactly agree with DC resistance measurements. These findings demonstrate that the so-called ‘Lebed magic angles’ at which DC AMRO dips are observed are, in fact, not ‘magic’ at all. Our data can easily be explained within a CAREER: Magnetic Resonance - From Materials Research to Science Education Stephen Hill, University of Florida, DMR-0239481 Are Lebed’s Magic Angles Truly Magic? See: S. Takahashi et al., Phys. Rev. B 72 024540 (2005). Also presented as an invited talk at the recent ISCOM conference.

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CAREER: Magnetic Resonance - From Materials Research to Science Education Stephen Hill, University of Florida, DMR-0239481. Are Lebed’s Magic Angles Truly Magic?. - PowerPoint PPT Presentation

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Page 1: Are Lebed’s Magic Angles Truly Magic?

We have performed high-frequency (microwave spectral range) Angle-dependent Magneto-Resistance Oscillation (AMRO) measurements in the low-dimensional organic conductor (TMTSF)2ClO4. We show that the angles at which AMRO dips are observed depend on the ratio of v/B, where v is the measurement frequency (40 – 150GHz) and B is the magnetic field strength. At v = 0, the data exactly agree with DC resistance measurements. These findings demonstrate that the so-called ‘Lebed magic angles’ at which DC AMRO dips are observed are, in fact, not ‘magic’ at all. Our data can easily be explained within a non-interacting Fermi-liquid picture, and are consistent with most other studies. These results should help resolve the long standing controversy surrounding the origin of the AMRO in the Q1D organic conductors based on the TMTSF donor.

CAREER: Magnetic Resonance - From Materials Research to Science Education

Stephen Hill, University of Florida, DMR-0239481Are Lebed’s Magic Angles Truly Magic?

• See: S. Takahashi et al., Phys. Rev. B 72 024540 (2005).

• Also presented as an invited talk at the recent ISCOM conference.

Page 2: Are Lebed’s Magic Angles Truly Magic?

Education: Diverse/international group of students (7 nationalities, 4 out of 10 are female, 1 minority): 1 postdoctoral; 5 PhD students; 1 masters student; two under-graduates. The PI participated in a Florida research experience program for high school students; REU student Emmitt Thompson presented poster at International conference.

Broader Impact:• Instrumentation has been tested at the Magnet

Lab in Tallahassee, FL, and will be made available to users once it is fully operational.

• The PI is organizing a workshop at UF to kick off the design phase for a proposed free-electron laser facility at the lab - a project with closely related scientific goals to this project.

CAREER: Magnetic Resonance - From Materials Research to Science Education

Stephen Hill, University of Florida, DMR-0239481

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