Pecularities of Hall effect in GaAs/δ〈Mn〉/GaAs/InxGa1−xAs/ GaAs (x ≈ 0.2) heterostructures with high Mn content

Abstract

Transport properties of GaAs/δ<Mn>/GaAs/In x Ga 1-x As/GaAs structures containing In x Ga 1-x As (х ≈ 0.2) quantum well (QW) and Mn delta layer (DL) with relatively high, about one Mn monolayer (ML) content, are studied. In these structures DL is separated from QW by GaAs spacer with the thickness d s = 2-5 nm. All structures possess a dielectric character of conductivity and demonstrate a maximum in the resistance temperature dependence R xx (T) at the temperature ≈ 46К which is usually associated with the Curie temperature T C of ferromagnetic (FM) transition in DL. However, it is found that the Hall effect concentration of holes p H in QW does not decrease below T C as one ordinary expects in similar systems. On the contrary, the dependence p H (T) experiences a minimum at T = 80-100 K depending on the spacer thickness, then increases at low temperatures more strongly than d s is smaller and reaches a giant value p H = (1-2)⋅10 13 cm -2 . Obtained results are interpreted in the terms of magnetic proximity effect of DL on QW, leading to induce spin polarization of the holes in QW. Strong structural and magnetic disorder in DL and QW, leading to the phase segregation in them is taken into consideration. The high p H value is explained as a result of compensation of the positive sign normal Hall effect component by the negative sign anomalous Hall effect component.2

Дельта-легирование соединениями марганца гетероструктур на основе GaAs

“…Кроме того, взаимодействие спи-нов ионов магнитной примеси с волновыми функци-ями квантованных носителей заряда (локализованных в квантовых ямах, в квантовых точках и др.) может проявиться в специфических магнитооптических и маг-нитотранспортных свойствах полупроводниковых гете-роструктур [6,7]. Поэтому крайне важно знать, каким может быть распределение магнитной примеси в объеме трехмерной матрицы вблизи квантово-размерных нано-объектов при удаленном легировании δ-слоями марган-ца (см., например, схематическую гетероструктуру на рис.…”