Nanoscale Physics  

The conductivity phenomena in Q1D electron system over superfluid helium at crystallization
V. A. Nikolaenko1, A. S. Smorodin2, S. S. Sokolov1
1 B.Verkin Institute for Low Temperature Physics and Engineering of NAS of Ukraine, Prospekt Nauky, 47, Kharkov 61103, Ukraine  
2 Okinawa Institute of Science and Technology, Okinawa 904-0495, Japan
E-mail: nikolaenko@ilt.kharkov.ua

The phenomena on phase boundary as well as at phase transitions attract the special attention of researchers in condensed matter physics. The conductivity, σ of one-dimensional (1D) or quasi-one-dimensional (Q1D) electron system is sensitive to boundary conditions of the system. The special place among 1D and Q1D systems is Q1D electron system over liquid helium. The system is formed by surface electrons pressed by electric field to the bottom of the liquid grooves in profiled substrate [1]. In present work we used the Q1D channels by width of 310-5 m for investigation value σ of electron channels at temperature range T = 0.5 –1.5K with the effective electron density 8.3·1012 m-2 (left picture) and 2.4·1013 m-2 (right picture). The transitions to electron crystal, Tc here are 0.65K and 1.1K.             
One can see lower Tc the row of eight parallel lines appears. The lines of σ - dependences decrease exponential with decreasing temperature. The activation energy for decreasing conductivity is Δ* = (T2 · Т1)·exp(σ1 / σ2) / (Т2 –Т1) (here σ1 and σ2  are the conductivities registered at Т1 or T2 accordingly). The calculated value of Δ*  is about 1 K. We believe the effect can be concern to Volf-Bregg constructive reflection of electron waves in rows at Wigner crystallization in Q1D electron channels. 

1.	Yu. Z. Kovdrya, Monarkha Yu.P. 1D electron system over liquid helium // Fiz. Nizk.Temp.–1986.-12.- P.1011-15; Yu. Z. Kovdrya, V.A. Nikolaenko. Q1D electron system over liquid helium //Fiz. Nizk.Temp. –1992.-18.- P.1278-80.