Inelastic electron scattering off a quantum dot in the cotunneling regime: the signature of mesoscopic Stoner instability

Abstract

We explore the inelastic electron scattering cross section off a quantum dot close to the Stoner instability. We focus on the regime of strong Coulomb blockade in which the scattering cross section is dominated by the cotunneling processes. For large enough exchange interaction the quantum dot acquires a finite total spin in the ground state. In this, so-called mesoscopic Stoner instability, regime we find that at low enough temperatures the inelastic scattering cross section (including the contribution due to an elastic electron spin-flip) for an electron with a low energy with respect to the chemical potential is different from the case of a magnetic impurity with the same spin. This difference stems from (i) presence of a low-lying many-body states of a quantum dot and (ii) the correlations of the tunneling amplitudes. Our results provide a possible explanation for absence of the dephasing rate saturation at low temperatures in recent experiment [N. Teneh, A. Yu. Kuntsevich, V. M. Pudalov, and M. Reznikov, Phys. Rev. Lett. 109, 226403 (2012)] in which existence of local spin droplets in disordered electron liquid has been unraveled.

14 pages, 3 figures

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Cited by in corpus (3)

• Novel Energy Scale in the Interacting 2D Electron System Evidenced from Transport and Thermodynamic Measurements
• Nonequilibirum noise spectrum and Coulomb-blockade-assisted Rabi interference in a double-dot Aharonov-Bohm interferometer
• Phase Separation in Two-Dimensional Electron Systems: Experimental View