A series of new infrared NLO semiconductors, ZnY6Si2S14, Al(x)Dy3(Si(y)Al(1-y))S7, and Al0.33Sm3SiS7.

ABSTRACT

Four new quaternary isostructural rare-earth thiosilicates, ZnY(6)Si(2)S(14) (1), Al(0.50)Dy(3)(Si(0.50)Al(0.50))S(7) (2), Al(0.38)Dy(3)(Si(0.85)Al(0.15))S(7) (3), and Al(0.33)Sm(3)SiS(7) (4), crystallized in the chiral and polar space group P6(3), have been prepared by a facile synthetic routine. Compounds 1-3 show strong second harmonic generation effects at 2.1 um with the intensities of 1, 2, and 3 being about 2, 2, and 1 times that of KTP (KTiOPO(4)), respectively. The calculated band structure of 1 implies that the optical absorptions of BLn(6)M(2)Q(14) and ALn(3)MQ(7) family compounds are mainly ascribed to the charge transitions from Q-p to Ln-4f (4d for Y) states. Compounds 2-4 exhibit antiferromagnetic-like interactions.