With the investigation of 2D monolayer, there is intensive study on ultra-small sized 1D nanomaterials such as nanoribbons, nanowires and nanoflakes etc. Here we have systematically elucidated the spin-dependent, shape and size dependent structural, electronic and magnetic properties of two transition metal dichalcogenide (TMD) nanoflakes namely: Cr${}_m$S${}_n$ and Cr${}_m$Se${}_n$ using density functional theory. Here we take the triangular and rhombic type configuration of nanoflakes. We found that the structural configuration becomes more stable as we increase the size of the nanoflakes. The HOMO-LUMO gaps increases with the increase in size of nanoflakes. The studied nanoflakes are magnetic semiconductor except two flakes Cr${}_{12}$S${}_{20}$ and Cr${}_8$S${}_{16}$ which are spin gapless semiconductors (SGS). So these efforts of nanoscaling helps us to engineer electronic devices at nanoscale. Also our spin dependent findings underscore the importance of TMDs nanoflakes for their future applications in spintronics, optoelectronics etc.

随着对二维单层的研究，对超小尺寸一维纳米材料如纳米带、纳米线和纳米薄片等进行了深入研究。在这里，我们系统地阐明了两个跃迁的自旋相关、形状和尺寸相关的结构、电子和磁性能金属二硫属化物 (TMD) 纳米薄片即： Cr${}_{米}$秒${}_n$ 和铬${}_{米}$硒${}_n$使用密度泛函理论。在这里，我们采用纳米薄片的三角形和菱形配置。我们发现随着我们增加纳米薄片的尺寸，结构配置变得更加稳定。HOMO-LUMO 间隙随着纳米薄片尺寸的增加而增加。所研究的纳米薄片是磁性半导体，除了两个薄片 Cr${}_{12}$秒${}_{20}$ 和铬${}_8$秒${}_{16}$自旋无间隙半导体（SGS）。因此，纳米尺度的这些努力有助于我们在纳米尺度上设计电子设备。此外，我们的自旋相关发现强调了TMD纳米薄片在自旋电子学、光电子学等未来应用中的重要性。