Large zero-field spin splitting in AlGaN/AlN/GaN/AlN heterostructures

WOS: 000266263300070This work describes Shubnikov-de Haas (SdH) measurements in Al0.22Ga0.78N/AlN/GaN/AlN heterostructures. Our experiments coupled with the analysis of the Hall data at various temperatures confirm the formation of a two-dimensional electron gas (2DEG) at the AlN/GaN interface. A beating pattern in the SdH oscillations is also observed and attributed to a zero-field spin splitting of the 2DEG first energy subband. The values of the effective spin-orbit coupling parameter and zero-field spin-split energy are estimated and compared with those reported in the literature. We show that zero-field spin-split energy tends to increase with increasing sheet electron density and that our value (12.75 meV) is the largest one reported in the literature for GaN-based heterostructures. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3120782]State of Planning Organization of TurkeyTurkiye Cumhuriyeti Kalkinma Bakanligi [2001K120590]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [104E090, 105E066, 105A005]; Engineering and Physical Sciences Research Council (UK)Engineering & Physical Sciences Research Council (EPSRC); Turkish Academy of Sciences (Turkey)Turkish Academy of SciencesThis work is supported by the State of Planning Organization of Turkey under Grant No. 2001K120590 and by TUBITAK under Project Nos. 104E090, 105E066, and 105A005. S. B. Lisesivdin acknowledges a 2214 coded international research scholarship from TUBITAK (Turkey), A. P. acknowledges support from the Engineering and Physical Sciences Research Council (UK) and E. O. acknowledges partial support from the Turkish Academy of Sciences (Turkey)