A huge Rashba splitting enhanced by an in-plane magnetic field is observed in non-magnetic InGaAs resonant tunneling diodes with GaAsSb barriers. At T = 4 K, the current resonances split by the Rashba effect reveal peak to valley ratios up to 2.5:1 and the energy spacing between the split peaks reaches 30 meV at B = 5 T. The observed peak splitting can be observed at temperatures up to T = 180 K and higher. The Rashba parameters determined on four different samples are between α = 0.38 eVÅ and α = 0.78 eV Å, which are consistent with theoretical values reported for InAs quantum wells under external electric fields.

A huge Rashba splitting enhanced by an in-plane magnetic field is observed in non-magnetic InGaAs resonant tunneling diodes with GaAsSb barriers. At T=4K, the current resonances split by the Rashba effect reveal peak to valley ratios up to 2.5:1 and the energy spacing between the split peaks reaches 30 meV at B=5T. The observed peak splitting can be observed at temperatures

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Large spontaneous spin splitting in gate-controlled two-dimensional electron gases at normal In 0.75 Ga 0.25 As/In 0.75 Al 0.25 As heterojunctionsThe authors report on two-dimensional electron gases realized in the In 0.53 Ga 0.47 As/GaAs 0.51 Sb 0.49 material system. For different doping levels, the sheet carrier densities were measured to be between 8.4. Â 10 10 and 8.3 Â 10 11 cm À2 . A maximum electron mobility of 42 700 cm 2 /V s was observed at a temperature of 60 K. In addition to alloy scattering, remote ionized impurity scattering is a limiting factor for this material combination, as the GaAs 0.51 Sb 0.49 barriers have the same low effective mass as the In 0.53 Ga 0.47 As channel and therefore allow the wavefunction to protrude into the barrier more than in other established material systems. Angle resolved Hall measurements revealed a strong influence of the crystallographic directions on the carrier mobility and two-dimensional electron population. An additional feature of these two-dimensional electron systems, originating from the fact that In 0.53 Ga 0.47 As and GaAs 0.51 Sb 0.49 show a type-II band alignment and comparable bandgap energies, is spin splitting, due to the Rashba effect, with a Rashba-parameter of 0.42 eVÅ .

In this work, the electrons effective masses in double barrier resonant tunneling diodes fabricated on the InGaAs/GaAsSb material system are investigated by magnetotunneling experiments. It is found that due to the nonparabolic band structure in this material system, the electron effective masses increase significantly on samples with smaller well width and higher resonance energies. Surprisingly, a decreasing effective mass is observed with increasing Landau levels index. This mass decrease can be explained in terms of the quantum confined Stark effect influencing the resonant level positions inside the resonant tunneling diodes.