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Resonantly enhanced tunneling in a double layer quantum hall ferromagnet
I B Spielman1, J P Eisenstein, L N Pfeiffer
1California Institute of Technology, Pasadena, California 91125, USA.
Physical Review Letters
|September 16, 2000
Summary
Strong interlayer correlations in parallel 2D electron systems cause a resonant tunneling enhancement at total Landau level filling. This occurs when crossing the boundary into a ferromagnetic quantized Hall state.
Area of Science:
- Condensed matter physics
- Quantum mechanics
- Materials science
Background:
- Interlayer Coulomb correlations significantly influence the behavior of parallel two-dimensional electron systems.
- Understanding quantum Hall states and phase transitions is crucial for novel electronic devices.
Purpose of the Study:
- To investigate the tunneling conductance in strongly correlated parallel 2D electron systems.
- To analyze the changes in tunneling spectrum at total Landau level filling nuT=1.
- To explore the relationship between tunneling enhancement and the Goldstone mode.
Main Methods:
- Experimental measurement of tunneling conductance.
- Fabrication of parallel two-dimensional electron systems.
- Analysis of the tunnel spectrum across different phases.
Main Results:
- A qualitative change in the tunnel spectrum was observed at nuT=1 when transitioning between compressible and ferromagnetic quantized Hall states.
- Equilibrium tunneling, typically suppressed in weakly coupled layers, was replaced by a significant resonant enhancement.
- The observed enhancement suggests a connection to the Goldstone mode of the broken symmetry ground state.
Conclusions:
- Strong interlayer correlations lead to distinct tunneling behaviors in 2D electron systems.
- The resonant enhancement is a key indicator of the ferromagnetic quantized Hall state.
- Further investigation into the Goldstone mode's role in this phenomenon is warranted.