Acoustical-Mode-Driven Electron-Phonon Coupling in Transition-Metal Diborides

Abstract

We show that the electron-phonon coupling in the transition-metal diborides NbB2 and TaB2 is dominated by the longitudinal acoustical (LA) mode, in contrast to the optical E_{2g} mode dominated coupling in MgB2. Our ab initio results, described in terms of phonon dispersion, linewidth, and partial electron-phonon coupling along Gamma to A, also show that (i) NbB2 and TaB2 have a relatively weak electron-phonon coupling, (ii) the E_{2g} linewidth is an order of magnitude larger in MgB2 than in NbB2 or TaB2, (iii) the E_{2g} frequency in NbB2 and TaB2 is considerably higher than in MgB2, and (iv) the LA frequency at A for TaB2 is almost half of that of MgB2 or NbB2.

4 pages, 4 figures, and 1 table

References in corpus (2)

• Electron-phonon interaction in transition metal diborides TB_2 (T=Zr, Nb, Ta) studied by point-contact spectroscopy
• Electron-Phonon Interaction in NbB_2 : A Comparison with MgB_2

Cited by in corpus (4)

• Lattice dynamics and electron-phonon coupling in transition metal diborides
• Theoretical Study of Electron-Phonon Interaction in ZrB2 and TaB2
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• Is Delta_{pi}-gap-only superconductivity possible in Mg_{1-x}Al_{x}B_{2} and Mg(B_{1-y}C_{y})_{2} alloys?