1. Materials 218 Class 1 Materials under pressure Ram Seshadri Materials Department, and Department of Chemistry and Biochemistry Materials Research Laboratory University of California, Santa Barbara CA 93106 http://www.mrl.ucsb.edu/~seshadri +++ seshadri@mrl.ucsb.edu Topics: (in no particular order) Methods of generating high pressures Synthesis under pressure Properties under pressure

2. Materials 218 Class 1 Materials under pressure, why care?

3. Materials 218 Class 1 Materials under pressure, the pioneer: Percy Bridgeman Percy Williams Bridgman (21 April 1882 – 20 August 1961) 1946 Nobel Prize in Physics wikimedia A modern system in the Huppertz lab at the University of Innsbruck

4. Materials 218 Class 1 Materials under pressure, the pioneer: Percy Bridgeman 10,000 kg cm –2 = 0.981 GPa ≈ 1 GPa = 10 kbar Bridgman speaks of 10 GPa pressures being attainable in 1946. Compressibility of ether, and Cs (from the Nobel lecture).

5. Materials 218 Class 1 Materials under pressure, the pioneer: Percy Bridgeman Volume compression of some elements. Note the phase transitions (from the Nobel lecture).

6. Materials 218 Class 1 Materials under pressure, the pioneer: Percy Bridgeman Electrical resistivity of some elements (from the Nobel lecture)

7. Materials 218 Class 1 Materials under pressure: Ice etc. The p–T diagram of H 2 O (D 2 O) and a new phase (Ice-XII, 0.2 Gpa to 0.6 GPa) Ti–Zr pressure cell, with external Ar pressure at a neutron diffractometer. Lobban, Finney, Kuhs, Nature 391 (1998) 268–270.

8. Materials 218 Class 1 Materials under pressure: An example of synthesis under pressure Bi 2 MnNiO 6, a ferromagnetic, ferroelectric (?) double perovskite: “Bulk sample of Bi2NiMnO6 was prepared from a stoichiometric mixture of Bi 2 O 3, NiO, and MnO 2. The starting material was charged into a gold capsule, treated at 6 GPa and 800 °C for 30 min in a cubic anvil-type high-pressure apparatus. Then it was slowly cooled to the room temperature for 4-50 h before releasing the pressure.” Azuma, Takata, Saito, Ishiwata, Shimakawa, Takano, Designed Ferromagnetic, Ferroelectric Bi 2 NiMnO 6, J. Am. Chem. Soc. 127 (2005) 8889-8892.

9. Materials 218 Class 1 Materials under pressure: An example of synthesis under pressure Bi 2 MnNiO 6, a ferromagnetic, ferroelectric (?) double perovskite: Azuma, Takata, Saito, Ishiwata, Shimakawa, Takano, Designed Ferromagnetic, Ferroelectric Bi 2 NiMnO 6, J. Am. Chem. Soc. 127 (2005) 8889-8892. Space group C2 (can support a polarization)

10. Materials 218 Class 1 Materials under pressure: In the earth MgSiO 3 (Mg 2 Si 2 O 6, pyroxene): ambient pressure, enstatite high-pressure, perovskite/ Bridgmanite ultra-high- pressure, post- perovskite/ CaIrO 3 structure (above 100 GPa)

11. Materials 218 Class 1 Materials under pressure: Bridgmanite Science 346 (2014) 1100–1102. The Tenham L6 chondrite: “MgSiO 3 -perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ~24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral.”

12. Materials 218 Class 1 Materials under pressure: Understanding phases under pressure Grochala, Hoffmann, Feng, Ashcroft, Angew. Chem. Int. Edn. 46 (2007) 3620–3642. “We will discuss in detail an overlapping hierarchy of responses to increased density: a) squeezing out van der Waals space (for molecular crystals); b) increasing coordination; c) decreasing the length of covalent bonds and the size of anions; and d) in an extreme regime, moving electrons off atoms and generating new modes of correlation.”

13. Materials 218 Class 1 Materials under pressure: Understanding phases under pressure Grochala, Hoffmann, Feng, Ashcroft, Angew. Chem. Int. Edn. 46 (2007) 3620–3642. Rules: 1.Van der Waals space is most easily compressed 2.Ionic and covalent structures, be they molecular or extended, respond to pressure by increasing coordination 3.Increased coordination is achieved relatively easily through donor– acceptor bonding, which shades over into multicenter bonding. Such multicenter bonding, electron-rich or electron-poor, is a mechanism for compactification (hence, a response to elevated pressure) for elements across the Periodic Table 4.Orbital-symmetry considerations will affect the chance that a high- pressure product survives return to metastability in the ambient-pressure world. 5.In ionic crystals, the anions are more compressible than the cations; therefore, the coordination number (especially that of the cations) increases at high pressure

14. Materials 218 Class 1 Materials under pressure: Understanding phases under pressure Grochala, Hoffmann, Feng, Ashcroft, Angew. Chem. Int. Edn. 46 (2007) 3620–3642. Rules (contd.): 6.All materials become metallic under sufficiently high pressure 7.Thinking about Peierls distortions (their enhancement and suppression) is helpful in understanding symmetrization (or its absence) in solids under high pressure 8.Under extremely high pressure, electrons may move off atoms, and new “non-nucleocentric” bonding schemes need to be devised 9.Close packing is the way, for a while. But keep an open mind—still denser packing may be achieved through electronic disproportionation and through nonclassical deformation of spherical electron densities. 10.Pressure may cause the occupation of orbitals that a chemist would not normally think are involved

15. Materials 218 Class 1 10123456789 KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn FrRaAc LaCePrNdPmSmErGdTbDyHoEuTmYbLu AcThPaUNpPuAmCmBkCfEsFmMdNoLr 01234567891011121314 NaMgAlSiPSClAr LiBeBCNOFNe HHe 123456789101112131415161718 The superconducting elements (bulk, ambient pressure) CRC Handbook of Physics and Chemistry [http://www.hbcpnetbase.com/] Materials under pressure

16. Materials 218 Class 1 10123456789 KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn FrRaAc LaCePrNdPmSmErGdTbDyHoEuTmYbLu AcThPaUNpPuAmCmBkCfEsFmMdNoLr 01234567891011121314 NaMgAlSiPSClAr LiBeBCNOFNe HHe 123456789101112131415161718 The magnetic(ally ordered) elements [Ferromagnetic or antiferromagnetic] CRC Handbook of Physics and Chemistry [http://www.hbcpnetbase.com/] Mn Fe Tm ferromagnet antiferro mixed Magnetism and superconductivity are largely incompatible Materials under pressure

17. Materials 218 Class 1 10123456789Al KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn FrRaAc LaCePrNdPmSmErGdTbDyHoEuTmYbLu AcThPaUNpPuAmCmBkCfEsFmMdNoLr 01234567891011121314 NaMgSiPSClAr LiBeBCNOFNe HHe 123456789101112131415161718 Some (new) superconducting elements (under pressure) Buzea, Robbie, Supercond. Sci. Technol. 18 (2005) R1-R8. impetus mutat res Pressure can drastically change electronic structure (for eg. Ba behaves like a transition metal) Materials under pressure

18. Materials 218 Class 1 Materials under pressure: The diamond anvil cell Weir, Lippincott, Van Valkenburg, Bunting, J. Res. Natl. Bur. Stand. 63A (1959) 55–62; Forman, Piermarini, Barnett, Block, Science 176 (1972) 284–285. Invented at NBS (now NIST):

19. Materials 218 Class 1 Materials under pressure: The diamond anvil cell Akella, Science and Technology Review of the LLNL, March 1996, pages 17–26. The modern DAC

20. Materials 218 Class 1 Materials under pressure: The diamond anvil cell Oganov, Ono, Nature 430 (2004) 445–448. Example of DAC research: MgSiO 3 at 118 GPa and 300 K.

21. Materials 218 Class 1 Materials under pressure: The Hugoniot locus (locus of single-shocked states) Li, Zhou, Li, Wu, Cai, Dai, Rev. Sci. Instr. 83 (2012) 053902(1–7). Shock compression increases p and T at the same time: The eg. of Ta

22. Materials 218 Class 1 Materials under pressure: The monster 500 TW experiment “The National Ignition Facility is the premier high energy density science facility in the world … major focus of NIF is a national effort to demonstrate ignition and thermonuclear burn in the laboratory … a variety of experiments to study matter at the extremes, including studies of material properties… A NIF experimental platform typically consists of an integrated laser, hohlraum, and diagnostic suite capable of providing well-characterized pressure, temperature, implosion, or other environments. Particular samples are then placed within the hohlraum and studied.”

23. Materials 218 Class 1 Materials under pressure: The monster experiment Smith et al. Nature 511 (2014) 330–333.

24. Materials 218 Class 1 Materials under pressure Smith et al. Nature 511 (2014) 330–333. “Top, the temporally resolved velocity interferometry record. Bottom, derived free-surface velocity u fs versus time. The target (inset) consists of a gold cylinder (hohlraum) 6 mm in diameter by 11 mm long, inside which the 351-nm wavelength laser light (purple beams) is converted to X-ray energy that is absorbed by the diamond sample attached to the side of the hohlraum. The X-rays ablate and ramp-compress the sample …”

25. Materials 218 Class 1 Materials under pressure Smith et al. Nature 511 (2014) 330–333. Hugoniots for compression of diamond to 5 TPa