Pressure-induced phases of TiS3. (A) Monoclinic crystal lattice of TiS3 (space group of P21/m (type-I)) at low pressure. The gray box outlines the periodic unit cell. Bond 1 (magenta) is 2.67 Å long, while the bonds 2, 3, and 4 (dark blue) are 2.49 Å long on average. To show clearly the embedded 1D chains, we use maroon and yellow S atoms to differentiate the two different (but equivalent) chains within a periodic unit cell. The S–S pair (labeled in orange) connects S atoms attached to the same Ti. (B) Left: A photograph of a Q1D TiS3 microstructure (seen as a dark line) on a white paper. Right: SEM image of the TiS3 whisker at low pressure. (C) Monoclinic crystal lattice of TiS3, P21/m (type-II), at intermediate pressure. The gray box outlines the periodic unit cell. The S–S bond (labeled in purple) connects S atoms attached to different Ti. (D) Cubic crystal lattice of the high-pressure phase (space group of Pm3m) in the ball-and-stick representation. (E) Cubic crystal lattice in the polyhedral representations. Credit: Nano Letters (2024). 10.1021/acs.nanolett.4c00824

When compressed, nanoribbons of titanium and sulfur can change properties dramatically, turning into materials with the ability to conduct electricity without losing energy, according to a study published in the journal Nano Letters.

The authors have made the discovery during their painstaking search for new that can transmit without loss of , a hot topic that has for long haunted the scientific community.

"Our research focuses on one such promising material: TiS3 nanoribbons, which are tiny, ribbon-like structures made of titanium and sulfur. In their natural state, TiS3 nanoribbons act as insulators, meaning they do not conduct electricity well," says Mahmoud Rabie Abdel-Hafez, an associate professor at University of Sharjah's Department of Applied Physics and Astronomy.

"However, we discovered that by applying to these nanoribbons, we could change their electrical properties dramatically," adds Abdel-Hafez, who is the study's main author.

The scientists exposed TiS3 to gradual pressure. As they increased the pressure, they found that the TiS3 system underwent a series of transitions, from being insulators to becoming metals and superconductors, for the first time.

TiS3 materials are known to work as good insulators, but it is the first time scientists have discovered that under pressure they can function as superconductors, paving the way for the development of superconducting materials.

"Superconductors are special because they can conduct electricity with zero energy loss, which is incredibly valuable for technological applications," says Abdel-Hafez. "[But] imagine a world where could be transmitted without any energy being wasted as heat. This would revolutionize how we use and distribute electricity, making everything from power grids to far more efficient."

It is exactly this potential which the authors tout as a breakthrough: the potential of TiS3 to turn into materials causing no waste when transmitting electricity. By carefully controlling the pressure applied to these materials, the authors identified the exact points where they changed from one state to another.

"This is significant because understanding these transitions helps us learn how to manipulate other materials in similar ways, bringing us closer to discovering or designing new superconductors that can operate at higher temperatures and more practical conditions," notes Abdel-Hafez .

The study shows that TiS3 has the potential to become such a material when subjected to the right conditions. By gradually increasing the pressure on the investigated materials, the authors observed that they transitioned from being insulators (poor conductors) to metals (good conductors) and finally to superconductors (perfect conductors with no energy loss).

(A) Temperature-pressure phase diagram of TiS3. (B) Photograph and SEM image of quasi-1D microstructure. Credit: Nano Letters (2024). 10.1021/acs.nanolett.4c00824

Discovering that TiS3 materials can become superconductors under pressure is certain to help scientists understand more about the conditions required for superconductivity. This knowledge is crucial for developing new materials that might be superconductors at higher, more practical temperatures, the authors maintain.

More information: Mahmoud Abdel-Hafiez et al, From Insulator to Superconductor: A Series of Pressure-Driven Transitions in Quasi-One-Dimensional TiS3 Nanoribbons, Nano Letters (2024). DOI: 10.1021/acs.nanolett.4c00824

Journal information: Nano Letters