Exchange interaction of electrons with Mn in hybrid AlSb/InAs/ZnMnTe structures

Abstract

The concept of spin-based electronics demands heterostructures possessing high electron mobility, pronounced ferromagnetic properties, and strong spin-orbit interaction (SOI).1,2 In particular, manganese doped diluted magnetic semiconductors (DMS) showing high Curie temperature and large Landé factor are in the focus of current research. While enhanced magnetic properties have been obtained in (Cd,Mn)Te-and (Ga,Mn)As-based quantum wells (QWs), the SOI in these materials is rather small. Thus, realization of DMS heterostructures based on materials which possess a strong SOI, e.g., InAs, becomes important. Most recently, it has been demonstrated that the incorporation of Mn into a heterostructure device containing an InAlAs/InGaAs QW leads to a two-dimensional hole gas.3 In these structures, the Mn ions are in close proximity to the InGaAs channel hosting the hole gas. While DMS hole systems with strong SOI have been realized and demonstrate very interesting magnetotransport properties, 4 the fabrication of InAs-based DMS with high mobility two-dimensional electron gas (2DEG) channels is still a challenge. The 2DEG is characterized by a simple parabolic band structure and much higher mobility compared to that of the holes, even in Mn-doped DMS structures like (Cd,Mn)Te QW (Ref. 5) features making 2DEG systems attractive for various applications. The only In(Mn)As-based superlattice with electron mobility l from 10 2 to 10 3 cm 2 /Vs has been realized in Ref. 6. Here, we report on the fabrication of Mn modulation doped structures with an InAs 2DEG channel. The QWs were grown applying III-V/II-VI "hybrid" technique following the recipes given in Ref. 7. The Mn layers have been inserted into the II-VI barrier. To explore the magnetic properties of the 2DEG, we investigated spin polarized electric currents induced by microwave (mw) radiation. 8,9 Our measurements show that hybrid AlSb/InAs/(Zn,Mn)Te QWs are characterized by enhanced magnetic properties which can be changed by tuning of the spatial position of Mn-doping layer as well as by the variation of temperature.The structures were grown on (001)-oriented GaAs semiinsulating substrates at temperature of 280 C. For the fabrication of AlSb/InAs/(Zn,Mn)Te heterovalent structures with Mn-containing barriers, we used two separated MBE setups. The first, Riber 32P, was employed to obtain the III-V part consisting of the 0.2 lm-thick GaAs and 2 lm-thick GaSb buffer layers capped with a 4 nm-thick AlSb barrier and a 15 nm-thick InAs QW (two last layers have common InSb-like interface). A (2.5 nm-GaSb/2.5 nm-AlSb) 10 superlattice was placed within the first third of the GaSb buffer to suppress propagation of misfit-induced threading dislocations. The II-VI parts of the structures were deposited pseudomorphically on the III-V part in the second two-chambers MBE setup (Semiteq) after the ex-situ sulfur chemical passivation in a 1M Na 2 S 9H 2 O solution of the top InAs layer. The coherent growth of ZnTe on InAs was initiated by simultaneous opening of Zn and Te fluxes onto ...

Interplay of Rashba/Dresselhaus spin splittings probed by photogalvanic spectroscopy –A review

“…An access to analysis of the SIA/BIA anisotropy even at technologically important room temperature provides investigation of several types of photocurrents belonging to the class of photogalvanic effects. These studies have been already used to demonstrate a possibility of the controllable variation of SIA by means of asymmetric delta‐doping; to design (110)’grown QWs showing record spin relaxation times and (001)’oriented QWs with fulfilled persistent spin helix state condition; to explore the role of segregation and crystallographic orientation in the SIA/BIA strength and anisotropy; resulted in observation of SIA/BIA in wurtzite materials and SiGe QWs and have been applied to study exchange interaction in diluted magnetic QWs . The fact that photogalvanic effects are very general and have been detected in a large number of various 2DES makes them a proper tool in the arsenal of methods sensitive to subtle details of SOI.…”