scholarly journals Compressed sodalite-like MgH6 as a potential high-temperature superconductor

RSC Advances ◽  
2015 ◽  
Vol 5 (73) ◽  
pp. 59292-59296 ◽  
Author(s):  
Xiaolei Feng ◽  
Jurong Zhang ◽  
Guoying Gao ◽  
Hanyu Liu ◽  
Hui Wang
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Critical Temperature ◽  
First Principles ◽  
High Temperature Superconductor ◽  
First Principles Calculations

First-principles calculations predicted a MgH6 phase with a high superconducting critical temperature of ∼260 K under high pressure.

scholarly journals Properties of Cu1-xWx alloys at high pressure and high temperature from first-principles calculations

2014 ◽  
Vol 63 (20) ◽  
pp. 206501
Author(s):  
Zhai Dong ◽  
Wei Zhao ◽  
Feng Zhi-Fang ◽  
Shao Xiao-Hong ◽  
Zhang Ping
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
First Principles ◽  
First Principles Calculations

Low-pressure superconductivity in lithium-doped methane predicted by first principles

2020 ◽  
pp. 2150032
Author(s):  
Ning Lu ◽  
Yu-Long Hai ◽  
Hai-Yan Lv ◽  
Wen-Jie Li ◽  
Chun-Lei Yang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
High Temperature ◽  
Crystal Field ◽  
First Principles ◽  
Pressure Range ◽  
High Temperature Superconductor ◽  
Low Pressure ◽  
First Principles Calculations ◽  
A Charge ◽  
Low Pressures

To explore the high-temperature superconductor at low pressures, we have investigated the crystal structures, electronic properties, and possible superconductivity in the case of methane (CH4) doped by lithium in the pressure range of [Formula: see text][Formula: see text]GPa, based on the first-principles calculations. The results show that Li-intercalated CH4 (Lix(CH4)[Formula: see text]) can realize metallization and superconductivity at low pressures, even 5[Formula: see text]GPa. We find that there is a charge transfer between Li and CH4, but the metallization is driven by the change of crystal field induce by doping instead of charge transfer. The critical temperture is predicted from 3.8[Formula: see text]K at 5[Formula: see text]GPa for LiCH4 to 12.1[Formula: see text]K at 100[Formula: see text]GPa for Li(CH4)4. The low-pressure superconductivity of Lix(CH4)[Formula: see text] can be further optimized by adjusting component and pressure.

scholarly journals Ternary superconducting cophosphorus hydrides stabilized via lithium

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Ziji Shao ◽  
Defang Duan ◽  
Yanbin Ma ◽  
Hongyu Yu ◽  
Hao Song ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Structure Prediction ◽  
Pressure Range ◽  
High Temperature Superconductor ◽  
High Pressures ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
Ternary Compounds ◽  
Stable Structures

Abstract Inspired by the diverse properties of sulfur hydrides and phosphorus hydrides, we combine first-principles calculations with structure prediction to search for stable structures of Li−P−H ternary compounds at high pressures with the aim of finding novel superconductors. It is found that phosphorus hydrides can be stabilized under pressure via additional doped lithium. Four stable stoichiometries LiPH3, LiPH4, LiPH6, and LiPH7 are uncovered in the pressure range of 100–300 GPa. Notably, we find an atomic LiPH6 with $$Pm\overline 3$$ P m 3 ¯ symmetry which is predicted to be a potential high-temperature superconductor with a Tc value of 150–167 K at 200 GPa and the Tc decreases upon compression. All the predicted stable ternary hydrides contain the P–H covalent frameworks with ionic lithium staying beside, but not for $$Pm\overline 3$$ P m 3 ¯ -LiPH6. We proposed a possible synthesis route for ternary lithium phosphorus hydrides: LiP + H2 → LiPHn, which could provide helpful and clear guidance to further experimental studies. Our work may provide some advice on further investigations on ternary superconductive hydrides at high pressure.

Defect Complexes and Non-Equilibrium Processes Underlying the P-Type Doping of GaN

1998 ◽  
Vol 537 ◽  
Author(s):  
Fernando A. Reboredo ◽  
Sokrates T. Pantelides
Keyword(s):  
High Temperature ◽  
Experimental Evidence ◽  
First Principles ◽  
Final Anneal ◽  
First Principles Calculations ◽  
Defect Complexes ◽  
Equilibrium Processes ◽  
Open Questions ◽  
High Temperature Anneal ◽  
P Type

AbstractIt is well known that hydrogen plays a key role in p-type doping of GaN. It is believed that H passivates substitutional Mg during growth by forming a Mgs-N-Hi complex; in subsequent annealing, H is removed, resulting in p-type doping. Several open questions have remained, however, such as experimental evidence for other complexes involving Mg and H and difficulties in accounting for the relatively high-temperature anneal needed to remove H. We present first principles calculations in terms of which we show that the doping process is in fact significantly more complex. In particular, interstitial Mg plays a major role in limiting p-type doping. Overall, several substitutional/interstitial complexes form and can bind H, with vibrational frequencies that account for hitherto unidentified observed lines. We predict that these defects, which limit doping efficiency, can be eliminated by annealing in an atmosphere of H and N prior to the final anneal that removes H.

Oxygen isotope effect in a high-temperature superconductor under high pressure

2007 ◽  
Vol 19 (42) ◽  
pp. 425236 ◽  
Author(s):  
Xiao-Jia Chen ◽  
Viktor V Struzhkin ◽  
Alexander F Goncharov ◽  
Russell J Hemley ◽  
Ho-kwang Mao
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Oxygen Isotope ◽  
Isotope Effect ◽  
High Temperature Superconductor
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