Nanoscale physics 

Rashba interaction in polysislicon layers at cryogenic temperatures
Druzhinin A.1,2, Ostrovskii  I.1, Khoverko Yu.1,2, Rogacki K.2
1Lviv Polytechnic National University. St.Bandera Str.,12, Lviv-79013, Ukraine. 
E-mail: khoverko@lp.edu.ua
2 Institute of Low Temperature and Structure Research PAS, Gajowicka Str., 95, Wroclaw 53-421, Poland.

Polysilicon studies were conducted in the SOI-structures in a wide range of concentrations (from 2.41018 to 1.7 1020 cm-3), which allowed to determine the effect of the level of doping on the magnetic transport properties of the material at cryogenic temperatures. Laser recrystallization method was used to govern the poly-Si layer concentration: the samples have of 2.41018 cm-3 and 1.7 1020 cm-3 boron impurities before and after laser recrystallization, respectively. In the temperature interval of 10-25 K, the thermal behavior of the poly-Si resistance with a concentration of charge carriers of 2.4 × 1018 cm-3 can be represented by the Mott law (lnρ~Т-1/4). The samples after laser recrystallization with impurity concentration of 1.7 1020 cm-3 demonstrate metallic conductivity in the range of cryogenic temperatures. The results of investigations of the influence of a magnetic field up to 14 T on the properties of fine-grained polysilicon layers are confirmed by the hopping conductance in such samples at temperatures of liquid helium, where conductivity is realized by localized admixture centers. The presence of a negative magnetic resistivity testifies to spin polarization, in which a significant contribution to transport of charge carries occurs through double-occupied admixture centers. [1]. Parameters of spin-orbital interaction can be estimated in the framework of the Rashba effect model [2]. Investigation of experimental data allowed to obtain the parameters of hopping conductance for low-dimensional poly-Si layers with p300K = 2.41018 сm-3, in particular, calculated values of the radius of localization, density of states and average length of jumps at localized levels, which are: α1=6 Å, g1=1.31021 eVcm-3, 31<R<36 Å for single-housed centers and α2=23 Å, g2=21019 eVcm-3 121<R<140 Å for double-occupied centers, respectively. 

1.	Druzhinin A., Khoverko Yu., Kogut I., Koretskii R. Properties of low-dimentional polysilicon in SOI structures for low temperature sensors // Advanced Materials Research.– 2014.– Vol. 854.– P. 49–55.
2.	Jansen R. Silicon spintronics // Nature Materials.–2012.– Vol. 11, P. 400–408.