Characterization of unidirectional charge states in NbSe2 nanoribbonlike structures

Nanoribbons derived from two-dimensional (2D) materials can exhibit extraordinary electronic properties that are not present in their monolayer counterparts. Fabricating nanoribbons of 2D materials with intrinsic collective electronic states and uncovering the underlying quantum confinement effects are fundamental concepts in both physics and nanotechnology. Monolayer NbSe2 is a model system in this regard, as it has been proved to host a 3 x 3 charge-density-wave ground state. However, discrete NbSe2 nanoribbons have not been produced yet. Here, we successfully fabricate quantities of NbSe2 nanoribbonlike structures, where the atoms spontaneously reconstruct into a 7 x 1 stripe phase. Our spectroscopic measurements further reveal a unidirectional charge density modulation in NbSe2 nanoribbonlike structures, with the charge states exhibiting an out-of-phase accumulation on the two sides of-0.15 V. These findings establish NbSe2 nanoribbons as an intriguing platform for exploring one-dimensional-confined collective electronic states, offering a stepping stone toward nanoelectronic devices.