We performed a chirality-controlled crystal growth of transition metal
disilicide NbSi2β and TaSi2β by using a laser-diode-heated floating
zone (LDFZ) method. The crystal chirality was evaluated in the crystals of
centimeters in length by performing single crystal X-ray diffraction as well as
probing a spin polarization originating from chirality-induced spin selectivity
(CISS) effect. The crystals of right-handed NbSi2β and of left-handed
TaSi2β were obtained in the conventional LDFZ crystal growth, while the
left-handed NbSi2β and right-handed TaSi2β crystals were grown by the
LDFZ method with the composition-gradient feed rods. The spin polarization via
the CISS was observed over centimeters in the NbSi2β single crystals and
the sign of the CISS signals was dependent on the chirality of crystals. The
correlation between the crystal chirality and CISS signals indicates that the
CISS measurements work as a non-destructive method for chirality determination
even in centimeter-long specimens.Comment: 9 pages, 6 figure