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Anisotropic conductivity and weak localization in HgTe quantum wells with a normal energy spectrum

G. M. Minkov, A. V. Germanenko, O. E. Rut, A. A. Sherstobitov, S. A. Dvoretski, and N. N. Mikhailov
Phys. Rev. B 88, 045323 – Published 30 July 2013
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  • INTRODUCTION
  • EXPERIMENTAL DETAILS
  • RESULTS AND DISCUSSION
  • CONCLUSION
  • ACKNOWLEDGEMENTS
  • APPENDICES
    • References

    Abstract

    The results of experimental study of interference induced magnetoconductivity in narrow quantum well HgTe with a normal energy spectrum are presented. Analysis is performed by taking into account the conductivity anisotropy. It is shown that the fitting parameter τϕ corresponding to the phase relaxation time increases in magnitude with the increasing conductivity (σ) and decreasing temperature following the 1/T law. Such a behavior is analogous to that observed in the usual two-dimensional systems with a simple energy spectrum and corresponds to the inelasticity of electron-electron interaction as the main mechanism of the phase relaxation. However, it drastically differs from that observed in the wide HgTe quantum wells with the inverted spectrum, in which τϕ, being obtained by the same way, is practically independent of σ. It is presumed that a different structure of the electron multicomponent wave function for the inverted and normal quantum wells could be the reason for such a discrepancy.

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    • Received 16 April 2013

    DOI:https://doi.org/10.1103/PhysRevB.88.045323

    ©2013 American Physical Society

    Authors & Affiliations

    G. M. Minkov1,2, A. V. Germanenko2, O. E. Rut2, A. A. Sherstobitov1,2, S. A. Dvoretski3, and N. N. Mikhailov3

    • 1Institute of Metal Physics RAS, 620990 Ekaterinburg, Russia
    • 2Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg, Russia
    • 3Institute of Semiconductor Physics RAS, 630090 Novosibirsk, Russia

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    Vol. 88, Iss. 4 — 15 July 2013

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    Images

    • Figure 1
      Figure 1
      (a) Architecture and (b) energy diagram of the structure under investigation. (c) The dispersion for the lowest electron (s1) and highest hole (h1) subbands calculated in the framework of the isotropic 6×6 kP model. The inset shows the electron density dependence of the effective mass for the electron subband s1. Symbols plot the data, and the line shows the calculated dependence.Reuse & Permissions
    • Figure 2
      Figure 2
      The gate voltage dependencies of (a) electron density and (b) conductivity obtained from the measurements on the standard Hall bar, shown in the inset. Circles and squares in (a) are data obtained from the Hall and SdH effect, respectively. (c) The conductivity dependencies of the conductivity anisotropy obtained from the measurements of nonlocal conductivity (squares) and from the measurements performed on the L-shaped Hall bar (circles). The lines are provided as a guide to the eye.Reuse & Permissions
    • Figure 3
      Figure 3
      The gate voltage dependence of the conductivity measured on the different arms of the L-shaped Hall bar shown in the inset.Reuse & Permissions
    • Figure 4
      Figure 4
      The dependencies of (a) σ1,2(B) and (b) Δσ1,2(B/Btr1,2) for the L-shaped Hall bar measured for Vg=0 V at T=1.4 K. Btr1=0.014 T, Btr2=0.056 T. The curve in (a) is σ2(B)×K=σ2(B)σ1(0)/σ2(0)=2σ2(B). The curves in (b) are the results of the best fit by Eq. (2) with the parameters given in the text.Reuse & Permissions
    • Figure 5
      Figure 5
      The values of Δσ1/K and Δσ2K plotted as functions of B/Btr′, Btr′=0.028 T, for Vg=0 V and T=1.4 K. The symbols are the data and the solid lines are the result of the best fit by Eq. (2) with the parameters given in the text.Reuse & Permissions
    • Figure 6
      Figure 6
      The temperature dependencies of τϕ and τs for two gate voltages Vg=−1 and 3 V. Solid and open symbols plot the data obtained from analysis of the dependencies Δσ1(B)/K and Δσ2(B)K, respectively. The dashed lines are provided as a guide to the eye.Reuse & Permissions
    • Figure 7
      Figure 7
      The conductivity dependence of τϕ and τs for the HgTe quantum well with inverted (d=9 nm) and normal (d=5 nm) energy spectrum obtained in Ref. 17 and this paper, respectively. The solid and dotted lines are calculated according to Ref. 18 with F0σ=0 and −0.5, respectively. The dashed lines are provided as a guide to the eye.Reuse & Permissions
    • Figure 8
      Figure 8
      (a) The solid lines are the dependence Δσ(b) calculated from Eqs. (A4) and (A7) for different Fermi energies with parameters shown in (b) and τ/τϕ=0.005. The dashed lines are the results of the best fit performed at b<0.3 by the HLN expression. (b) The parameters τ/τm, τ/τA, and τ/τSO calculated from Eqs. (A4, A5, A6), and the fitting parameters τ/τs and τ/τϕ plotted as a function of the Fermi energy.Reuse & Permissions
    • Figure 9
      Figure 9
      The gate voltage dependence of σ1 and σ2 measured for arms 1 and 2 (solid symbols) as compared to that of σxx and σyy, found as described in the text. The inset illustrates the orientation of the principal axes x and y of the conductivity tensor in the coordinate system of the sample.Reuse & Permissions
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