Electronic structure and electron-phonon coupling in TiH$$_2$$
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Calculations using first principles methods and strong coupling theory are carried out to understand the electronic structure and superconductivity in cubic and tetragonal TiH$$_2$$. A large electronic density of states at the Fermi level in the cubic phase arises from Ti-$$t_{2g}$$ states and leads to a structural instability against tetragonal distortion at low temperatures. However, constraining the in-plane lattice constants diminishes the energy gain associated with the tetragonal distortion, allowing the cubic phase to be stable at low temperatures. Furthermore, calculated phonon dispersions show decoupled acoustic and optic modes arising from Ti and H vibrations, respectively and frequencies of optic modes to be rather high. The cubic phase has a large electron-phonon coupling parameter $$\lambda$$ and critical temperature of several K. Contribution of the hydrogen sublattice to $$\lambda$$ is found to be small in this material, which we understand from strong coupling theory to be due to the small H-$$s$$ DOS at the Fermi level and high energy of hydrogen modes at the tetrahedral sites.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1266003
- Journal Information:
- Scientific Reports, Vol. 6; ISSN 2045-2322
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Materials informatics based on evolutionary algorithms: Application to search for superconducting hydrogen compounds
|
journal | November 2019 |
Effect of electrons scattered by optical phonons on superconductivity in ( , Ti, V, Se)
|
journal | July 2018 |
Structural and Superconducting Properties of Tungsten Hydrides Under High Pressure
|
journal | September 2018 |
Predicting novel superconducting hydrides using machine learning approaches | text | January 2020 |
Similar Records
Scanning electron microscopy, X-ray diffraction and thermal analysis study of the TiH{sub 2} foaming agent
Electronic properties and electron-phonon coupling in zirconium and niobium hydrides