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

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.

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.

scholarly journals Mechanical properties and band structure of CdSe and CdTe nanostructures at high pressure - a first-principles study

2019 ◽  
Vol 13 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Natarajan Kishore ◽  
Veerappan Nagarajan ◽  
Ramanathan Chandiramouli
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Shear Modulus ◽  
Band Structure ◽  
First Principles ◽  
Pressure Range ◽  
Uniaxial Pressure ◽  
First Principles Calculations ◽  
Zinc Blende ◽  
Cauchy Pressure

First-principles calculations for CdSe and CdTe nanostructures were carried out to study their mechanical properties and band structure under the uniaxial pressure range of 0 to 50GPa. It was presumed that the CdSe and CdTe nanostructures exist in the zinc-blende phase under high pressure. The mechanical properties, such as elastic constants, bulk modulus, shear modulus and Young?s modulus, were explored. Furthermore, Cauchy pressure, Poisson?s ratio and Pugh?s criterion were studied under high pressure for both CdSe and CdTe nanostructures, and the results show that they exhibit ductile property. The band structure studies of CdSe and CdTe were also investigated. The findings show that the mechanical properties and the band structures of CdSe and CdTe can be tailored with high pressure.

COMPARATIVE STUDY OF THE STRUCTURAL AND ELECTRONIC PROPERTIES OF BN(5, 5) AND C(5, 5) NANOTUBES UNDER PRESSURE

2010 ◽  
Vol 24 (24) ◽  
pp. 4851-4859
Author(s):  
KAIHUA HE ◽  
GUANG ZHENG ◽  
GANG CHEN ◽  
QILI CHEN ◽  
MIAO WAN ◽  
...  
Keyword(s):  
High Pressure ◽  
Comparative Study ◽  
Charge Density ◽  
Band Gap ◽  
Electronic Properties ◽  
Cross Section ◽  
First Principles ◽  
First Principles Calculations ◽  
Zinc Blende ◽  
Structural And Electronic Properties

The structural and electronic properties of BN(5, 5) and C(5, 5) nanotubes under pressure are studied by using first principles calculations. In our study range, BN(5, 5) undergoes obvious elliptical distortion, while for C(5, 5) the cross section first becomes an ellipse and then, under further pressure, is flattened. The band gap of BN(5, 5) decreases with increasing pressure, which is inverse to that of zinc blende BN, whereas for C(5, 5) the metallicity is always preserved under high pressure. The population of charge density indicates that intertube bonding is formed under pressure. We also find that BN(5, 5) may collapse, and a new polymer material based on C(5, 5) is formed by applying pressure.

Sign in / Sign up

Export Citation Format

Share Document