News

Tina Arh, Matjaž Gomilšek, Matej Pregelj, Martin Klanjšek and Andrej Zorko from the Solid State Physics Department and Peter Prelovšek from the Department of Theoretical Physics at the “Jožef Stefan” Institute, in collaboration with researchers from United Kingdom, USA and China, have published a paper “Origin of Magnetic Ordering in a Structurally Perfect Quantum Kagome Antiferromagnet” in Physical Review Letters. They confirmed more than a decade old theoretical prediction of a quantum critical point of a kagome antiferromagnet between a quantum spin liquid and a magnetically ordered state, induced by the Dzyaloshinskii-Moriya magnetic anisotropy. YCu3(OH)6Cl3 is the first known material with a perfect kagome lattice without any impurities, in which the magnetic anisotropy can be studied in isolation from other perturbations. Understanding the mechanism of magnetic ordering in this material is crucial for understanding the stability of enigmatic quantum spin liquids.

Andrej Zorko from the Department of Condensed Matter Physics at Jožef Stefan Institute and the Physics department at the Faculty of Mathematics and Physics, University of Ljubljana, was part of the international research team that confirmed the gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu3(OH)6Cl2. Their research, which was published in the Nature Physics journal, disproved the decades old conviction that a spin-gap must exist in this material and shone new light on the enigmatic state of this spin liquid. This experimental conclusion aligns with the most recent theories which propose a gapless Dirac spin liquid as the ground state of the Heisenberg kagome antiferromagnet.

A team of researchers from the Faculty of Mathematics and Physics and Faculty of Medicine, University of Ljubljana, and »Jožef Stefan« Institute, including Uroš Tkalec from our department, have studied previously unresearched dynamic chiral states which arise before the homeotropic to flow-aligned transition. In the article published in the Nature Communicationsjournal, they explain the mechanism of phase transitions between topologically different states of pressure driven liquid crytal with a phenomenological model based on the anisotropy of elastic constants and completed the phase diagram of all observed hydrodynamic states. These concepts could also be used in lyotropic and active nematic liquids with nematic order.

A team of researchers from the Faculty of Mathematics and Physics and Faculty of Medicine, University of Ljubljana, and »Jožef Stefan« Institute, including Uroš Tkalec from our department, have studied previously unresearched dynamic chiral states which arise before the homeotropic to flow-aligned transition. In the article published in the Nature Communicationsjournal, they explain the mechanism of phase transitions between topologically different states of pressure driven liquid crytal with a phenomenological model based on the anisotropy of elastic constants and completed the phase diagram of all observed hydrodynamic states. These concepts could also be used in lyotropic and active nematic liquids with nematic order.

At the international conference European C-MetAC Days 2019, held in December 2019 at the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany, Darja Gačnik received the award for the best oral presentation in the young scientists’ category. In her presentation Superconductivity in Ti–Zr–Hf–(Sn,Ni,Nb) high-entropy alloys she presented her research of superconductivity in a new type of metal alloys, called high-entropy alloys. The research results she presented were uncovered in collaboration with her co-workers at the Department of Condensed Matter Physics (S. Vrtnik, A. Jelen, M. Krnel, P. Koželj, J. Dolinšek) and dr. Qiangom Hujem from the Institute of Applied Physics at the Jiangxi Academy of Sciences, Nanchang, China.