New material design capable of controlling temperature at which converts from insulator to conductor paves way for novel superconductors

 

In a groundbreaking endeavor, scientists have devised a revolutionary synthetic material design poised to revolutionize electronic devices by transcending the limitations of traditional transistors. This novel advancement, achieved through collaborative efforts between researchers from the Indian Institute of Science (IISc), Japan, Denmark, and the United States, promises to redefine the landscape of electronic switches by overcoming the longstanding challenge of electronic 'traffic jams'.

Conventional materials are categorized as either electrical conductors or insulators. However, correlated electron materials present a unique class that exhibits a transition from insulator to metal under specific conditions, typically temperature-dependent. This transition, while significant, poses challenges for applications such as electronic switches that necessitate consistent operation at ambient temperatures.

Led by luminaries like Prof. Naga Phani and his team at the Solid State and Structural Chemistry Unit, IISc Bangalore, researchers have engineered a three-layer synthetic material structure to manipulate the temperature at which this transition occurs. This innovative design comprises an 'active' channel layer undergoing the metal to insulator transition, a charge reservoir layer capable of regulating electron flow into the active layer, and a charge-regulating spacer layer facilitating controlled electron transfer between the reservoir and active layers.

Critical to the success of this endeavor is the precise preparation of nanometer-thick, atomically smooth layers, achieved th

rough pulsed laser deposition—a technique akin to atom-by-atom spray-painting. The researchers meticulously characterized the layers using an atomic force microscope (AFM), optimizing conditions such as temperature, pressure, and growth rate for synthesizing this synthetic material stack.

Published in Nature Communications, the research showcases the use of Vanadium oxide (VO2) to demonstrate the controlled electron 'drip' into the active layer, surpassing a billion-trillion electrons per cubic centimeter. Unlike conventional doping methods, which alter crystal structures, this novel approach eliminates the need for impurities, preserving material integrity. Moreover, the researchers devised easily replicable amorphous-layer designs for the reservoir and spacer layers.

Beyond its immediate applications, this breakthrough facilitates the exploration and manipulation of exotic materials exhibiting dual insulator-conductor characteristics. Moreover, it sheds light on the enigmatic electronic 'traffic jams' underlying insulating behaviors in correlated electron materials, challenging existing paradigms.

Looking ahead, scientists envision extending this research to explore other exotic materials, such as superconductors, and devising novel devices harnessing phase transitions within synthetic structures. The proposed electronic control of phase transitions holds promise for elucidating quantum critical points, with potential applications spanning classical and quantum computing realms.

In essence, this pioneering synthetic material design not only transcends conventional limitations in electronic switches but also heralds a new era of scientific inquiry into the fundamental properties of materials, with profound implications for future technologies.

References:

Publications: https://www.nature.com/articles/s41467-023-41816-3

 

Published by Department of Science and Technology on 15 th March 2024