  We performed a crystal growth to obtain chirality-controlled enantiopure
crystals using a laser-diode-heated floating zone (LDFZ) method with a
composition-gradient feed rod. It has been argued that the crystal handedness
of $T$Si ($T$ : transition metal) is fixed depending on $T$ in the case of the
ones grown by the conventional methods. We found that right-handed single
crystals of CoSi and MnSi were grown from the composition gradient feed rods
that consist of FeSi--CoSi and FeSi--MnSi, respectively. The obtained CoSi and
MnSi crystals inherit the chirality from the seed part of FeSi, which grows in
a right-handed structure, and thus have the chirality opposite to that for the
crystals in the literature. The LDFZ method with the feed rods with various
combinations of $T$Si compounds enables a flexible control of the chirality of
$T$Si and will be useful for clarifying the interplay between the crystalline
chirality and chirality-induced physical responses.
