However, in recent years scientists have increasingly explored 2D semiconductors, ultra-thin materials made from just one or a few layers of atoms. Their super-thin structure changes how electrons behave, potentially enabling new capabilities in future semiconductor devices.<\/p>\n
The team now focused on electrons in a state known as a Wigner solid<\/a>, an exotic state of matter in which free electrons freeze into a rigid, crystal-like grid instead of flowing like a fluid. In conventional semiconductor devices, electrons behave more like independent particles moving through a material. This state is known as a Fermi liquid.<\/p>\n In a Wigner solid, however, repulsion between electrons becomes dominant. The electrons separate, become largely immobile, and also organize themselves into relatively orderly patterns. Scientists have previously struggled to directly observe how defects affect these strongly interacting electrons. <\/p>\n Now, the researchers created a specialized device that placed MoSe2 between a graphite layer and layers of silicon and boron nitride. Tiny holes in the graphite allowed the microscope\u2019s metal tip to scan the semiconductor underneath. They then studied samples with different defect levels and adjusted electron density to track the shift between Wigner solid and Fermi liquid states.<\/p>\n Defects alter electron behavior<\/p>\n The images revealed massive differences depending on the number of defects present. When many defects were present, the electrons became locked into an unexpectedly stable Wigner solid<\/a> with irregular and disordered patterns.<\/p>\n With fewer defects, the electrons instead formed more orderly triangular, crystal-like patterns. These transitioned more readily into the Fermi liquid state. <\/p>\n Crommie described his first reaction to seeing the unexpected images. \u201cIt was exciting to see the Wigner solid melt into liquid-like waves splashing up against defects,\u201d he elaborated. \u201cWe could see how electrons respond to defects in very different ways.\u201d<\/p>\n He explained that certain defects acted like large potholes while others acted like tiny speed bumps. The team also needed to confirm that the unusual structures were genuine electron behavior rather than artifacts created by the microscope.<\/p>\n For this, they used Quantum Monte Carlo simulations to calculate how strongly interacting electrons should respond to random defects according to quantum mechanics. The simulations closely matched the microscope images.<\/p>\n Crommie believes that controlling the location and type of defects could become increasingly important as electronic components shrink. \u201cIt also helped us better understand the physics underlying the behaviors we observed in our images,\u201d he concluded in a press release<\/a>.<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/09\/Z2_92072f.jpg\" "\\"US")
Experimental and simulated images show electrons transitioning from a Wigner solid to a Fermi liquid. Credit: Berkeley Lab<\/a><\/p>\n