Experimental determination of the Rashba coefficient in InSb/InAlSb quantum wells at zero magnetic field and elevated temperatures

• Published in: Journal of physics. Condensed matter Vol. 23; no. 3; pp. 035801 - 7
• Main Authors: Leontiadou, M A, Litvinenko, K L, Gilbertson, A M, Pidgeon, C R, Branford, W R, Cohen, L F, Fearn, M, Ashley, T, Emeny, M T, Murdin, B N, Clowes, S K
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 26.01.2011; Institute of Physics
• Subjects: Asymmetry; Coefficients; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electric fields; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; High temperature; Magnetic fields; Physics; Quantum wells; Splitting; Spin dynamics; Zero field splitting; Rashba effect; Zeeman effect; Indium antimonides; Quantum wells; Magnetic field effects; Electron mobility; Carrier density; Electrostatic potential; Aluminium Indium Antimonides Mixed; Spintronics
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/23/3/035801

We report the optical measurement of the spin dynamics at elevated temperatures and in zero magnetic field for two types of degenerately doped n-InSb quantum wells (QWs), one asymmetric (sample A) and one symmetric (sample B) with regards to the electrostatic potential across the QW. Making use of three directly determined experimental parameters: the spin lifetime, τ(s), the sheet carrier concentration, n, and the electron mobility, μ, we directly extract the zero-field spin splitting. For the asymmetric sample where the Rashba interaction is the dominant source of spin splitting, we deduce a room temperature Rashba parameter of α = 0.09 ± 0.1 eV Å which is in good agreement with calculations and we estimate the Rashba coefficient α(0) (a figure of merit for the ease with which electron spins can be modulated via an electric field). We review the merits/limitations of this approach and the implications of our findings for spintronic devices.