QFS 2016 Book of Abstracts

Abstracts

O2.8 Mobility of Electrons on 3 He- 4 He Mixture Ikegami Hiroki(1), Sato Daisuke(1), Kim Kitak(2), Choi Hyoungsoon(2), and Kono Kimitoshi(1) 1) The Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan 2) Department of Physics, KAIST, Daejeon 305-701, Republic of Korea Adsorbed 3 He atoms on a free surface of 3 He- 4 He mixture liquid offer an ideal two-dimensional (2D) Fermi system with a tunable interaction between 3 He, showing 2D Fermi degeneracy and potentially superfluidity. To study properties of the 2D 3 He, we performed a first systematic measurement of mobility of electrons trapped on the free surface down to 10 mK by varying the concentration of 3 He from 0.5 to 6.1 %. We found that the mobility in the Wigner crystal regime is understood in terms of the viscosity of the bulk liquid at temperatures higher than about 100 mK and the specular reflection of ballistic 3 He quasiparticles below 100 mK. We discuss the influence of the 2D 3 He on the mobility. O2.9 Stick-slip motion of a single electron chain on the surface of liquid helium Rees David(1,2), Beysengulov Niyaz (2,3), Lin Juhn-Jong(1,2), Kono Kimitoshi (1,2,3) 1) National Chiao Tung University, Institute of Physics, NCTU-RIKEN Joint Research Laboratory, Hsinchu 300, Taiwan 2) RIKEN CEMS, Wako 351-0198, Japan 3) Kazan Federal University, Institute of Physics, KFU-RIKEN Joint Research Laboratory, Kazan 420008, Russia A quasi-1D electron crystal moving across the surface of liquid helium performs stick-slip motion (SSM) due to repeated coupling and decoupling with surface capillary waves (ripplons)[1]. The decoupling threshold force is larger when the electrons form well-defined rows, due to the enhancement of resonant ripplon scattering. Here we show that continuously reducing the number of electrons in the crystal therefore results in a modulation of the SSM as the number of rows changes. We find that the SSM persists even in the limit of the single electron chain. The influence of reduced dimensionality on the electron-ripplon coupling will be discussed. [1] D. G. Rees et al., PRL 116 (2016).

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