Sobre o evento:
This lecture will provide a brief overview of the history of superconductors’ discovery. Over the past 115 years, improving the superconducting transition temperature, understanding the underlying mechanisms, and designing novel superconducting materials have become central challenges — often described as the “holy grail” of condensed matter physics. In the past three decades, the combination of high-pressure techniques with advanced characterization methods has led to record-breaking superconducting temperatures and the discovery of new superconducting systems. These achievements — ranging from sample synthesis under extreme pressure – temperature (P–T) conditions to in-situ structural determination and property measurements — have significantly advanced superconductivity research.
In this lecture, I will highlight recent collaborative projects in which sample structures were studied in situ under high pressure using synchrotron X-ray diffraction (XRD) in diamond anvil cells (DAC) at both ambient and cryogenic temperatures. Selected examples include pure elements (Ti, Sc), binary metal hydrides (Ca–H, Hf–H, Lu–H, Nb–H, Yb–H and beyond), and oxide systems (La–Ni–O, Ba–K–Bi–O). These cases will be discussed in the context of their XRD results, corresponding first-principles calculations, and updated phase diagrams in low-temperature, high-pressure regimes. Additional examples — such as 2H-Cu₀.₆₅TaS₂ and the cuprate Pr₀.₈₇LaCe₀.₁₃CuO₄₊δ — will be briefly presented, focusing on pressure-induced Lifshitz transitions that alter Fermi surface topology, as well as associated electronic structural and property changes.
Minibiografia do palestrante:
Prof. Dr. Arthur Haozhe Liu is staff scientist at the Center for High Pressure Science & Technology Advanced Research (HPSTAR) since 2014. He graduated from Jilin University, China in 1991, and received his Ph. D from Institute of Metal Research, CAS in 1997. He had working experience on high pressure projects at following institutions: Harbin Institute of Technology, China (2007-2014), HPCAT at APS, Carnegie Institution of Washington/Argonne National Laboratory (2003-2007); Mineral Physics Institute, Stony Brook University/X17 Beamline, NSLS, Brookhaven National Laboratory (2002-2003); Max Planck Institute for Solid State Research (2000-2001); and Institute of Physics, CAS (1997-1999). Prof. Liu served as co-chair in the AIRAPT-26 Conference in 2017, and LAM-15 Conference in 2013, respectively. He also served as the Chair of IUCr High Pressure Commission during 2017 – 2021, and executive committee member of AIRAPT during 2017-2023. He currently served as co-editor of Journal of Applied Crystallography, Acting Chair of Asian Conference of High Pressure Research. Current scientific interest is materials physics and mineral physics under high pressure conditions. Research topics include pressure induced transitions in crystalline and non-crystalline or melting samples; structure and property relationship for materials under high pressure extreme conditions, using multiples advanced synchrotron radiation techniques, such as X-ray diffraction and scattering, high energy X-ray PDF method, absorption base and diffraction base tomography, XPCS, etc.
Acessos:
