Qi-Jun Hong

Systems Tested

Ta (0 and 200 GPa, bcc), Na (30-120 GPa, bcc/fcc), NaCl, La2Zr2O7 (La2O3-2ZrO2), the Hf-Ta-C-N systems, Al, Si, HfO2, Fe (330 GPa), Ti (bcc) and many more…

m.p.: melting point calculated by SLUSCHI.
If not specified, PAW-PBE is employed in the calculations.
HSE: melting point after HSE correction. (important for semiconductors)
# MD: total number of MD trajectories.
CPU hours are measured as / converted to TACC Stampede.
days: the physical time it takes. SLUSCHI is currently optimized to lower the CPU cost, rather the physical time. In order to reduce the physical time, user may manually explore temperature of interest. However, this may increase CPU hours.
“early runs” are calculations performed at early stage of method development. Hence the efficiency is relatively low compared to “sluschi”.

poor results and reason | good results

systems m.p./K HSE/K expt./K DFT PP rad / Å kmesh # MD cpu hours days note
Al 1040±13 933 Al 12 (1/2,1/2,1/2) 19 5,400 7 sluschi
Al 999±21  1054 933 Al 10 Auto 30 58 16,000 15 sluschi
Ti_v 1811±47 1941 Ti_v 9 Auto 20 49  15,500 21 sluschi
Ti_v 1750±25 1971 1941 Ti_v 10 Auto 20 26 7,900 17 sluschi
Ti_pv 1952±45 1941 Ti_pv 10 (1/4,1/4,1/4)  48 20,000 20 sluschi
Ti_pv 60GPa 2505±47 ? Ti_pv 10 (1/4,1/4,1/4)  46 39,500 17 sluschi
Si 724±47 1687 Si 10 Auto 10 25 1,000 2 sluschi
Si 1378±24 1785 1687 Si 10 Auto 20 19 7,500 15 el. DOS change, require HSE
Si 1364±37 1687 Si 12 Auto 20 20 27,700 27 sluschi
diamond,100GPa 4307±8 4250 C 10  gamma 45 313,000 168 sluschi
Ru_v 2435±32 2607 Ru_v 10  Auto 20  30 88,000 37 sluschi
Ru_pv 2550±34 2607 Ru_pv 10 (1/4,1/4,1/4)  33 139,000 51 sluschi
Ru ternary alloys 2564±40 n/a  pv 10 (1/4,1/4,1/4)  23 247,000 80 sluschi
Hf,bcc  2562±31 2506 Hf 10 (1/2,1/2,1/2) 115 14,900 12 sluschi
Hf,hcp  2122±50 n/a Hf 10 (1/2,1/2,1/2) 50 25,800 21 sluschi, hcp not stable at MT
HfO2  2327±47 3031 valence 10 gamma 33 79,000 sluschi
HfO2 PBE+U  3486±91 3031 Hf_pv 10 gamma 34 99,600 sluschi
HfO2 PBE+U  3313±81 3031 Hf_pv 12 gamma 25 running ionic, use large $rad
ZrO2 2988 valence 10 Auto 20 running
Ta_v 2986±41 3290 Ta_v 10 (0,1/4,1/4) 38 32,000 23 early runs, low efficiency
Ta_pv 3194±40 3290 Ta_pv 10 (0,1/4,1/4) 38 54,000 24 early runs, low efficiency
Ta_pv_PW91 3066±51 3290 Ta_pv 10 (0,1/4,1/4) 38 38,000 68 PW91 [1]
Ta_pv,200GPa 7953±69 n/a Ta_pv 10 (1/4,1/4,1/4) 80 150,000 48 sluschi, high efficiency [4]
W 3497±54 3695 W 10 A20 22 35,900 49 sluschi
W_pv 3470±45 3695 W_pv 10 (1/4,1/4,1/4) 30 38,500 18 sluschi
Na 15 GPa 657±8 810, 698 ? Na_pv 10.4 (0,1/4,1/4) 55 47,000 24 bcc, expt under dispute, e.g.,
Na 26 GPa 750±16 706 970 ? Na_pv 9.8 (0,1/4,1/4) 52 26,000  17 Zha, Boehler vs. Gregoryanz
Na 40 GPa 742±17 950 ? Na_pv 9.4 (0,1/4,1/4) 74 54,000 37 SLUSCHI results agree with
Na 55 GPa 716±12 810 ? Na_pv 9.0 (0,1/4,1/4) 56 64,000  31 Eshet and Desjarlais (theory).
Na 80 GPa 674±20 700 ? Na_pv 10.9 (0,1/4,1/4) 55 170,000 67 fcc, expt under dispute
Na 100 GPa 662±14 450 ? Na_pv 10.6 (0,1/4,1/4) 48 57,000 28 fcc, expt under dispute
Na 120 GPa 579±27 ? Na_pv 10.4 (0,1/4,1/4) 88 150,000 77 fcc, expt under dispute
NaCl 1014±18 1074 valence 11 gamma 59 24,000 50 early runs, low efficiency
La2Zr2O7 2420±27 2630 2530 Zr_v, La_sv 10 gamma 64  575,000 210 [2]
Hf-Ta-C-N valence 10  –  –  – [3]

1. Qi-Jun Hong and Axel van de Walle, Solid-liquid coexistence in small systems: A statistical method to calculate melting temperatures. Journal of Chemical Physics 139 (9), 094114 (2013). [DOI]
2. Qi-Jun Hong, Sergey V. Ushakov, Alexandra Navrotsky, Axel van de Walle, Combined computational and experimental investigation of the refractory properties of La2Zr2O7Acta Materialia 84, 275-282 (2015). [DOI]
3. Qi-Jun Hong and Axel van de Walle, Prediction of the material with highest melting temperature from quantum mechanics. Physical Review B Rapid Communications, 92, 020104(R) (2015). [DOI]
4. Ljubomir Miljacic, Steven Demers, Qi-Jun Hong and Axel van de Walle, Equation of state of solid, liquid and gaseous tantalum from first principles. Calphad: Computer Coupling of Phase Diagrams and Thermochemistry51, 133-143 (2015). [DOI (open access)].


01:03:2016
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