Characterization of the electronic properties of YB$_4$ and YB$_6$ using $^{11}$B NMR and first-principles calculations
| dc.creator | Jäger, B. | |
| dc.creator | Paluch, S. | |
| dc.creator | Wolf, W. | |
| dc.creator | Herzig, P. | |
| dc.creator | Żogał, O. J. | |
| dc.creator | Shitsevalova, N. | |
| dc.creator | Paderno, Y. | |
| dc.date | 2003-10-25 | |
| dc.date.accessioned | 2026-07-07T02:54:25Z | |
| dc.date.available | 2026-07-07T02:54:25Z | |
| dc.description | Two compounds, tetragonal YB$_4$ and cubic YB$_6$, have been investigated by electric-field gradient (EFG) and Knight shift measurements at the boron sites using the $^{11}$B nuclear magnetic resonance (NMR) technique and by performing first-principles calculations. In YB$_6$ $^{11}$B ($I=3/2$) NMR spectra reveal patterns typical for an axially symmetric field gradient with a quadrupole coupling frequency of $ν_Q=600\pm15$ kHz. In the second boride (YB$_4$) three different EFGs were observed corresponding to the three inequivalent crystallographic sites for the boron atoms ($4h$, $4e$, and $8j$). They correspond to: $ν_Q(4h)=700\pm30$ kHz with an asymmetry parameter $η=0.02\pm0.02$, $ν_Q(4e)=515\pm30$ kHz, $η=0.00+0.02/-0.00$, and $ν_Q(8j)=515\pm40$ kHz, $η=0.46\pm0.08$. The Knight shifts measured by Magic-Angle Spinning (MAS) NMR at room temperature are very small being $0.6\pm8$ ppm and $-1\pm8$ ppm for YB$_4$ and YB$_6$, respectively. For the theoretical calculations structure optimizations were performed as a first step. For the obtained structural parameters the EFGs were computed within the local-density approximation. Very satisfactory agreement between experimental and theoretical results is obtained both for the structural parameters and the B EFGs thus confirming the underlying structural models. In addition to the EFGs, band structures, densities of states, and valence-electron densities are presented and the bonding situation in the two yttrium borides is discussed. The band-structure results are compatible with the very low values for the Knight shifts mentioned above. | |
| dc.description | 22 pages, 6 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0310602 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0310602 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/22536 | |
| dc.subject | Condensed Matter | |
| dc.title | Characterization of the electronic properties of YB$_4$ and YB$_6$ using $^{11}$B NMR and first-principles calculations | |
| dc.type | text |