Weak antilocalization of holes in HgTe quantum wells with a normal energy spectrum

Abstract

The results of experimental study of quantum interference effects in small magnetic fields in narrow HgTe quantum wells of hole-type conductivity with a normal energy spectrum are presented. Interpretation of the data is performed with taking into account the strong spin-orbit splitting of the energy spectrum of the two-dimensional hole subband. It is shown that the phase relaxation time found from the analysis of the shape of magnetoconductivity curves in the case when the Fermi level lies in the monotonic part of the energy spectrum of the valence band behaves itself analogously to that observed in narrow HgTe quantum wells of electron-type conductivity. It increases in magnitude with the increasing conductivity and decreasing temperature following the 1/T law. Such a behavior corresponds to the inelasticity of electron-electron interaction as the main mechanism of the phase relaxation and agrees well with the theoretical predictions. For the higher conductivity, despite the fact that the dephasing time remains inversely proportional to the temperature, it strongly decreases with the increasing conductivity. It is presumed that the reason for such a peculiarity could be nonmonotonic character of the hole energy spectrum. An additional channel of inelastic interaction occurs when the Fermi level approaches the secondary maxima in the depth of the valence band. © 2015 American Physical Society.