Abstract
We present high field magneto-transport data from a range of 30nm wide InSb/InAlSb quantum wells. The low temperature carrier mobility of the samples studied ranged from 18.4 to 39.5 m2V-1s-1 with carrier densities between 1.5x1015 and 3.28x1015 m-2. Room temperature mobilities are reported in excess of 6 m2V-1s-1. It is found that the Landau level broadening decreases with carrier density and beating patterns are observed in the magnetoresistance with non-zero node amplitudes in samples with the narrowest broadening despite the presence of a large g-factor. The beating is attributed to Rashba splitting phenomenon and Rashba coupling parameters are extracted from the difference in spin populations for a range of samples and gate biases. The influence of Landau level broadening and spin-dependent scattering rates on the observation of beating in the Shubnikov-de Haas oscillations is investigated by simulations of the magnetoconductance. Data with non-zero beat node amplitudes are accompanied by asymmetric peaks in the Fourier transform, which are successfully reproduced by introducing a spin-dependent broadening in the simulations. It is found that the low-energy (majority) spin up state suffers more scattering than the high-energy (minority) spin down state and that the absence of beating patterns in the majority of (lower density) samples can be attributed to the same effect when the magnitude of the level broadening is large.
Highlights
InSb has been the subject of numerous experimental and theoretical studies due to characteristic features of the bulk crystal such as a narrow band gap and light effective mass resulting in a high intrinsic electron mobility.1 Twodimensional electron gases2DEGsformed in InSb quantum wellsQWsoffer a number of advantages for device applications
Despite the difficulties associated with highly mismatched epitaxy, recent advances in the growth of highquality InSb heterostructures on GaAs substrates have resulted in room-temperature extrinsic carrier mobilities reported in excess of 5 m2 V−1 s−1, making InSb QWs attractive for high-speed electronicshigh electron mobility transistors,2 ballistic transport devices, and magnetic sensor applications such as nonmagnetic read heads based on extraordinary magnetoresistance
To characterize the 2DEGs, the sheet carrier density n2D at zero gate bias was determined both from low-field Hall effect measurements and from the SdH fundamental frequency which agreed to within 2% indicating that no parallel conduction paths are present
Summary
InSb has been the subject of numerous experimental and theoretical studies due to characteristic features of the bulk crystal such as a narrow band gap and light effective mass resulting in a high intrinsic electron mobility. Twodimensional electron gases2DEGsformed in InSb quantum wellsQWsoffer a number of advantages for device applications. A large SO coupling results in a short spin lifetime, which has been measured optically to be s ϳ 0.3 ps at 300 K in 20 nm InSb/InAlSb QWsRef. 4͒; tuning of the SO splitting via the Rashba interaction in InSb QWs, a prerequisite for most spintronic device proposals, has not been demonstrated.. Only a small number of elegant but indirect measurements of the SO coupling have been made in InSb QWs and to the best of our knowledge none use beating in xx This is because of the large g factor in narrow gap materials which results in the SdH oscillations being dominated by Zeeman splitting at relatively small fieldscompared to wider gap systems such as InGaAs QWs, making the observation of beating patterns challenging.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
