University of Minnesota
School of Physics & Astronomy

Condensed Matter Seminar

Tuesday, November 21st 2017
12:20 pm:
Speaker: Alexander Kuntsevich, P. N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia
Subject: Spin magnetization and entropy measurements in two-dimensional systems

We apply recharging technique to measure derivatives dS/dn and dM/dn (S and and M are the entropy and the magnetization per unit area, n is the carrier density) in two-dimensional gated systems. In particular, we demonstrate that 2D metal-to-insulator transition is accompanied by formation of spin droplets. We also detect fingerprints of these droplets in transport properties of the system. Entropy measurements reveal signatures of electron-electron interactions in both Fermi liquid (T<< E_F) and correlated plasma (T~E_F) regime. In the quantum Hall effect gaps, entropy decreases significantly. In the Fermi-liquid regime (high densities)S goes to zero as temperature decreases as S \propto T, thus independently checking the 3rd law of thermodynamics.

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