Supplementary Figures

Transcription

1 Supplementary Figures Supplementary Figure S1: CDF TEM image taken using the 111 diamond diffraction ring. The image shows that the semi-ball consists of randomly oriented diamond nanocrystals. Ring ED pattern (shown as insert) is indexed to the face-centered cubic a 3.57Å unit cell of diamond. 1

2 Supplementary Figure S2: Microphotograph of the gold-coated NCD micro-ball of ~15 µm in diameter compressed in a Ne pressure medium at 23 GPa. 2

3 Supplementary Figure S3: Example of the Raman spectra of diamond taken from the culet of the upper diamond anvil of the DAC in experiments on compressibility of a NCD ball in a conventional diamond anvil cell. The upper spectrum is taken directly from the point, where the NCD sphere touched the upper anvil ( over NCD sphere ); the lower spectrum corresponds to the point on the same anvil but above Ne pressure medium ( over neon ). For pressure determination from the change in the position of the high frequency edge of the diamond Raman line see Ref. 21 and references therein. 3

4 Supplementary Figure S4: Diffraction patterns collected at 13-IDD (λ= Å) from different points over the NCD micro-ball compressed in a Ne pressure transmitting medium. Spatial steps between different patterns were of 3 µm; the X-ray beam used to scan the sample had a size of ~3 µm at FWHM in vertical direction. The pressure in the DAC chamber determined from Ne was 49(1) GPa. ( D stays for diamond s reflections, and Ne for reflections of neon; the diffraction pattern collected over the center of the NCD ball shows obvious splitting of the Ne diffraction lines). 4

5 a b Supplementary Figure S5: Schematic diagram of the double-stage diamond anvil cell. (a) A general view. (b) An enlarged view of the pressure chamber. Primary anvils are made of single crystal diamonds, while second-stage anvils are semi-balls of nanocrystalline diamond. 5

6 Pressure at the sample, GPa Pressure in Ne transmitting medium, GPa Supplementary Figure S6: The pressure on the sample of Re compressed between secondary anvils as a function pressure in the solid Ne medium surrounding the secondary anvils with the sample. 6

7 Unit cell volume, Å Pressure, GPa Supplementary Figure S7: The pressure dependence of the unit cell volume of Re. Red circles are experimental points as determined in Experiment #1 with the Au pressure standard 26 ; dark-red squares as determined in Experiment #2 with pressure obtained using the BM4 EOS of Re established in Experiment #1). Continues blue line is a result of fitting experimental data using the BM4 EOS (K 300 =342(6) GPa, K =6.15(15), K = (4), V 0 =29.46(1) Å 3 /unit cell); dashed green line the BM3 EOS due to fitting the data collected up to 165 GPa (K 300 = 353(3) GPa, K =5.80(7)); dashed short-long pink line is the BM3 EOS by Vohra et al. (Ref. 29), dotted green line is BM4 by Jeanloz et al. (Ref. 22). 7

8 600 Normalized pressure, GPa Strain Supplementary Figure S8: F-f plot for all data-sets collected on Re in this study. Continues line is the linear fit of the data collected up to 165 GPa in a conventional DAC with K 300 = 353(3) GPa, K =5.80(7) and it clearly shows that the BM3 EOS failed to describe high-pressure data-points. 8

9 c/a Pressure, GPa Supplementary Figure S9: Variation of the lattice parameters c/a ratio as a function of pressure as determined in the present study. 9

10 a b b Supplementary Figure S10: Examples of the diffraction patterns collected in ultrahigh pressure experiments with secondary diamond anvils. (a) Experiment #1. (b) Experiment #2. In Experiment #1 pressure was determined using Au as an internal standard; in Experiment #2 - using Re itself (see text and Table 1). * denotes positions of the (111) reflection of NCD visible in some patterns; x denotes positions of weak Ne reflections (from neon probably trapped between the primary and secondary anvils). The upper diffraction pattern in panel (b) was collected outside the secondary anvil stage from the Ne medium. 10

11 Supplementary Figure S11: EELS carbon K-edge spectrum of the NCD sample. The carbon K-edge starting at 285 ev shows all the typical signatures for carbon in a sp 3 (σ*) environment (diamond). Almost no π*contribution, typical of sp 2 bonded carbon, is present at 285 ev, indicating that the sp 2 -hybridized carbon content in the material is extremely low

12 Supplementary Reference 36. Egerton R.F Electron Energy-Loss Spectroscopy in the Electron Microscope. Springer, (2011). 12