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Spin texture and magnetoroton excitations at nu=1/3
Javier G Groshaus1, Irene Dujovne, Yann Gallais
1Physics & Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA. jgg@phys.columbia.edu
Physical Review Letters
|March 21, 2008
Summary
Spin texture (ST) excitations at nu=1/3 were observed for the first time, revealing two simultaneous spin flips. Their energy crosses with magnetorotons at a critical Zeeman-to-Coulomb energy ratio, with ST intensity surprisingly increasing with temperature.
Area of Science:
- Condensed Matter Physics
- Quantum Hall Effect Physics
Background:
- The fractional quantum Hall effect (FQE) at filling factor nu=1/3 is a rich area of condensed matter physics.
- Understanding the nature of excitations, such as spin texture (ST) excitations, is crucial for characterizing FQE states.
Purpose of the Study:
- To directly observe and characterize neutral spin texture (ST) excitations at nu=1/3.
- To investigate the energy spectrum and temperature dependence of ST excitations and their relation to other FQE modes.
Main Methods:
- Resonant inelastic light scattering was employed to directly observe ST excitations.
- The study analyzed the energy of ST modes as a function of in-plane magnetic field.
- Temperature dependence of ST mode intensity was measured.
Main Results:
- Neutral spin texture (ST) excitations at nu=1/3 were directly observed for the first time, involving two simultaneous spin flips.
- The ST energy was found to be below the magnetoroton minimum at low magnetic fields.
- A critical ratio of Zeeman and Coulomb energies (eta(c)=0.020+/-0.001) was identified where ST and magnetoroton mode energies cross.
- ST mode intensity unexpectedly increased with temperature, even as magnetoroton modes collapsed.
Conclusions:
- The observed temperature dependence suggests a competition between coexisting phases supporting different excitations at nu=1/3.
- ST excitations play a significant role in activated transport phenomena at nu=1/3.
- These findings provide new insights into the complex nature of excitations in fractional quantum Hall states.
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