Origins of ultrafast response and ultralow energy consumption in quasi-two-dimensional monatomic phase-change radio-frequency switch

Chalcogenide is an essential construction material for emerging nanoelectro-optical memories and radio-frequency (rf) switches, yet the latter still lacks comprehensive insights from theoretical mechanisms to device components. Here, we conceive of a directly heated chalcogenide-based phase-change rf switch with two-dimensional constrained Sb, a pivotal component of microwave switches capable of low energy consumption and ultrafast responses. In their quasi-two-dimensional amorphous counterparts, Peierls distortion is consolidated with highly localized electrons elevating the electrical resistivity of the scale-shrinking Sb that originates from quantum confinement effects, favoring low-Joule-heat energy barriers. The fabricated Sb-based phase-change rf switch operates with insertion loss of less than 1.2 dB and isolation of greater than 18 dB (up to 67 GHz). The total switch energy consumption can be as low as 1.1μJ, with over 3 orders of magnitude switching ratio. The ultrafast recrystallization process in the dimensional limit benefits from glass homogeneity along with the topological rearrangement of the three- to fourfold rings, explaining the 300-ns ultrafast response of the rf switch regarding geometrical-physical relevance. This work provides insights into chalcogenide-based assembly for rf switches that allow for future reconfiguration of wireless and 6G communication systems.