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Keywords:

  • Mesoscopic physics;
  • Orbital magnetism;
  • Statistical properties of spectra

Abstract

We study the magnetic response of mesoscopic quantum dots in the ballistic regime where the mean free path le is larger that the size L of the sample, yet smaller than L(KFL)d−1. In this regime, disorder plays an important role. Employing a semiclassical picture we calculate the contribution of long tranjectories which are strongly affected by static disorder and which differ sharply from those of clean systems. In the case of a magnetic field, they give rise to a large linear paramagnetic susceptibility (which is disorder independent), whose magnitude is in agreement with recent experimental results. In the case of a Aharonov-Bohm flux, the susceptibility is disorder dependent and is proportional to the mean free path as in the diffusive regime. We also discuss the corresponding non-linear susceptibilities.