skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Electronic structure and electron-phonon coupling in TiH$$_2$$

Abstract

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.

Authors:
 [1];  [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1266003
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; electronic structure; superconducting properties and materials

Citation Formats

Shanavas, Kavungal Veedu, Lindsay, Lucas R., and Parker, David S. Electronic structure and electron-phonon coupling in TiH$_2$. United States: N. p., 2016. Web. doi:10.1038/srep28102.
Shanavas, Kavungal Veedu, Lindsay, Lucas R., & Parker, David S. Electronic structure and electron-phonon coupling in TiH$_2$. United States. doi:10.1038/srep28102.
Shanavas, Kavungal Veedu, Lindsay, Lucas R., and Parker, David S. Wed . "Electronic structure and electron-phonon coupling in TiH$_2$". United States. doi:10.1038/srep28102. https://www.osti.gov/servlets/purl/1266003.
@article{osti_1266003,
title = {Electronic structure and electron-phonon coupling in TiH$_2$},
author = {Shanavas, Kavungal Veedu and Lindsay, Lucas R. and Parker, David S.},
abstractNote = {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.},
doi = {10.1038/srep28102},
journal = {Scientific Reports},
number = ,
volume = 6,
place = {United States},
year = {2016},
month = {6}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Metallic Hydrogen: A High-Temperature Superconductor?
journal, December 1968


General trend for pressurized superconducting hydrogen-dense materials
journal, January 2010

  • Kim, D. Y.; Scheicher, R. H.; Mao, H. -k.
  • Proceedings of the National Academy of Sciences, Vol. 107, Issue 7
  • DOI: 10.1073/pnas.0914462107

Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system
journal, August 2015

  • Drozdov, A. P.; Eremets, M. I.; Troyan, I. A.
  • Nature, Vol. 525, Issue 7567
  • DOI: 10.1038/nature14964

Pressure-induced metallization of dense (H2S)2H2 with high-Tc superconductivity
journal, November 2014

  • Duan, Defang; Liu, Yunxian; Tian, Fubo
  • Scientific Reports, Vol. 4, Issue 1
  • DOI: 10.1038/srep06968

Pressure-induced decomposition of solid hydrogen sulfide
journal, May 2015


Electron-phonon coupling and superconductivity in metal-hydrogen systems
journal, August 1984


Superconductivity of Hydrides and Deuterides of Thorium
journal, September 1970


Superconductivity in the Ti-D system under pressure
journal, December 1998

  • Bashkin, I. O.; Nefedova, M. V.; Tissen, V. G.
  • Physics of the Solid State, Vol. 40, Issue 12
  • DOI: 10.1134/1.1130711

Transition Temperature of Strong-Coupled Superconductors
journal, March 1968


First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X=H, D, and T) system
journal, February 2008


Electronically driven tetragonal distortion in TiH2
journal, January 1979


Electronic structure and energetics of the tetragonal distortion for TiH 2 , ZrH 2 , and HfH 2 : A first-principles study
journal, November 2009


Electronic properties and electron-phonon coupling in zirconium and niobium hydrides
journal, January 1982


Structure and stability of high pressure synthesized Mg–TM hydrides (TM = Ti, Zr, Hf, V, Nb and Ta) as possible new hydrogen rich hydrides for hydrogen storage
journal, January 2009

  • Moser, David; Bull, Daniel James; Sato, Toyoto
  • Journal of Materials Chemistry, Vol. 19, Issue 43
  • DOI: 10.1039/b911263d

Thermocrystallography of higher hydrides of titanium and zirconium
journal, January 1958


Electronic structure of Ba 3 Cu Sb 2 O 9 : A candidate quantum spin liquid compound
journal, February 2014


Influence of the Phonon Spectra of In-Tl Alloys on the Superconducting Transition Temperatures
journal, August 1970


Properties of boson-exchange superconductors
journal, October 1990


Beyond Eliashberg Superconductivity in MgB 2 : Anharmonicity, Two-Phonon Scattering, and Multiple Gaps
journal, August 2001


Cubic H 3 S around 200 GPa: An atomic hydrogen superconductor stabilized by sulfur
journal, May 2015


Electron-Phonon Interactions, d Resonances, and Superconductivity in Transition Metals
journal, March 1972


Generalized Gradient Approximation Made Simple
journal, October 1996

  • Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
  • Physical Review Letters, Vol. 77, Issue 18, p. 3865-3868
  • DOI: 10.1103/PhysRevLett.77.3865

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996