Welcome to HPSynC
A Gateway for High-Pressure Scientists to Beamlines of the APS

Dehydrogenation of goethite in Earth’s deep lower mantle
The hydrogen cycling in the deep Earth. Image courtesy Qingyang Hu.
In Earth interior, water (H2O) plays an important role in rock physics but geoscientists rarely treat water in its decomposable forms, like hydrogen plus oxygen. However, new work from a team led by HPSTAR director, Dave Mao, has identified the hydrogen can escape from the water under lower mantle conditions. Their results were published in Proceeding of the National Academic Science, U.S.A.More...

The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals.
The origin of uptrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals
Over last 60 years, efforts to enhance piezoelectricity generally resort to tuning the long-range ferroelectric phase transition. In the work published in the recent issue of Nature Communications (doi:10.1038/ncomms13807), the researchers revealed that small amount of nanoscale local inhomogeneity may dramatically improve the piezoelectric responses (50-80%) of a ferroelectric crystal.More...

Pressure-Induced Bandgap Optimization in Lead-Based Perovskites with Prolonged Carrier Lifetime and Ambient Retainability
Pressure-Induced Bandgap Optimaization in Lead-Based Perovskites with Prolonged Carrier Lifetime and Ambient Retainability
For the first time, scientists have reached the Shockley-Queisser theory optimized bandgap for single-junction solar cells in lead-based perovskites. A new study led by HPSTAR scientists Dr.Gang Liu and Dr. Dave Mao, report an unprecedentedly tuned bandgap of the Shockley–Queisser limit and double-prolonged carrier lifetime in formamidinium lead triiodide (HC(NH2)2PbI3) in the latest issue of Advanced Functional Materials (DOI: 10.1002/adfm.201604208).More...

Pressure-Driven Cooperative Spin-Crossover, Large-Volume Collapse, and Semiconductor-to-Metal Transition in Manganese(II) Honeycomb Lattices
Pressure-Driven Cooperative Spin-Crossover
Spin crossover (SCO), an intriguing phenomenon that magnetic ions can switch between high-spin (HS) and low-spin (LS) states in response to light irradiation or temperature, is mostly observed as a spectacular molecular magnetism in 3d4-3d7 metal complexes. A joint team of researchers from UNLV, HPSynC and HPSTAR reported their breakthrough in pursuing "cooperative" pressure-driven SCO in J. Am. Chem. Soc. (DOI: 10.1021/jacs.6b10225). An abrupt pressure-driven SCO accompanying with large lattice collapses and semiconductor-to-metal transitions was achieved in two-dimensional honeycomb lattices, MnPS3 and MnPSe3, for the first time. The work opens a new avenue for the exploration of pressure-responsive multifunctional materials. More...

Pressure-Induced New Topological Weyl Semimetal Phase in TaAs
TaAs
A joint team co-led by HPSTAR scientist Wenge Yang studied the envolution of electronic and structural properties of Weyl semimetal TaAs using multiple methods. They found a pressure-induced new Weyl semimetallic phase with isoenergetic 12 Weyl nodes in TaAs. The study is published in the journal Physical Reviews Letters (DOI:https://doi.org/10.1103/PhysRevLett.117.146402). More...

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