October_2021_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 1 5 SELF-HEALING PIEZOELECTRIC CRYSTAL Researchers from the Indian Insti- tute of Science Education and Research in Kolkata, the Indian Institute of Tech- nology Kharagpur, and RWTH Aachen University in Germany discovered a type of piezoelectric molecular crystal capable of autonomous self-healing. Previous efforts to develop self-healing materials have yielded some results in- cluding polymers, gels, and other mate- rials that can heal themselves to some degree after an injury. To date, these technologies have shared one thing in common—they are all soft. In the new study, scientists tackled the challenge of developing a self-healing hard ma- terial. In this case, that meant figuring out how to get a dense material, made of molecules arranged in a regular way, to heal when ripped apart. The work involved studying piezo- electric molecular crystals, which are capable of converting mechanical en- ergy into electricity. The team rea- soned that the inherent properties of such crystals should lend themselves to self-healing due to their attractive forces. After extensive trial and error, the researchers settled on bipyrazole RESEARCH TRACKS organic crystals and grew sample crys- tals in tiny needle shapes, 2-mm long by 0.2-mm wide. Next, they applied just enough pressure to make them break and then watched as they bounced back into straight needles, with no ev- idence of the break remaining. Testing of the crystal with a polarization mi- croscope system showed that the ma- terial had truly healed. The team says such crystals could find use in optical and nanoprobing devices, or perhaps in video screens, enabling smartphones to heal themselves after being dropped. www.rwth-aachen.de. CANDIDATE SUPER- CONDUCTOR ANNOUNCED Since receiving a $25 million grant in 2019 to become the first National Science Foundation Quantum Found- ry, researchers at the University of California, Santa Barbara (UCSB) af- filiated with the foundry have been working to develop materials that can enable quantum information-based technologies. Applications include quantum computing, communications, sensing, and simulation, among oth- ers. Now, UCSB materials engineering professor Stephen Wilson and multiple co-authors, including key collaborators A new type of piezoelectric molecular crystal is capable of self-healing. Courtesy of CC0 Public Domain. at Princeton University, are studying a new material developed in the Quan- tum Foundry as a candidate supercon- ductor that could be useful in future quantum computation. The group’s most recent paper, “Discovery of Unconventional Chiral Charge Order in Kagome Superconduc- tor KV 3 Sb 5 ” is published in Nature Mate- rials. Wilson says that the peculiar na- ture of the self-organized patterning of electrons is the focus of the current work. KV 3 Sb 5 was discovered to be a rare metal built from kagome lattice planes, and one that also superconducts. Some of the material’s other characteris- tics led researchers to speculate that charges in it may form tiny loops of cur- rent that create local magnetic fields. The role of Wilson’s group was to make the material and characterize its bulk properties. The Princeton team then used high-resolution scanning tunneling microscopy to identify what they believe are the signatures of such a state, which “are also hypothesized to exist in other anomalous supercon- ductors, such as those that supercon- duct at high temperature, though it has not been definitively shown,” accord- ing to Wilson. If KV 3 Sb 5 turns out to be what it is suspected of being, it could be used to make a topological qubit useful in quantum information applications. ucsb.edu . A newmaterial developed in the Quantum Foundry could be useful in future quantum computation. Courtesy of Pixabay/ CC0 Public Domain.