Temperature-dependent nuclear magnetic resonance inCuInX2 (X=S,Se,Te)chalcopyrite-structure compounds

摘要: The NMR spectra of $^{63}\mathrm{Cu}$ and $^{115}\mathrm{In}$ in CuIn${\mathrm{S}}_{2}$, CuIn${\mathrm{Se}}_{2}$, CuIn${\mathrm{Te}}_{2}$ have been measured between room temperature 550\ifmmode^\circ\else\textdegree\fi{}C. effects motional narrowing phase transitions on the shape width absorption were evaluated. In all three compounds, signal shows narrowing. For ${\mathrm{Cu}}_{1.00}$${\mathrm{In}}_{1.00}$${\mathrm{S}}_{2.00}$ mean jump frequency ${\mathrm{Cu}}^{+}$ ions, $\ensuremath{\nu}({\mathrm{Cu}}^{+})$, is $2\ifmmode\times\else\texttimes\fi{}{10}^{13}\mathrm{exp}[\ensuremath{-}\frac{(1.25\ifmmode\pm\else\textpm\fi{}0.10 \mathrm{eV})}{\mathrm{kT}}]$ ${\mathrm{s}}^{\ensuremath{-}1}$. both CuIn${\mathrm{Se}}_{2}$ CuIn${\mathrm{Te}}_{2}$, $\ensuremath{\nu}({\mathrm{Cu}}^{+})$ about 3\ifmmode\times\else\texttimes\fi{}${10}^{3}$ ${\mathrm{s}}^{\ensuremath{-}1}$ at 350\ifmmode^\circ\else\textdegree\fi{}C. copper-deficient ${\mathrm{Cu}}_{0.96}$${\mathrm{In}}_{1.02}$${\mathrm{S}}_{2.00}$ no was observed up to However, line CuIn${\mathrm{S}}_{2}$ depends copper-to-indium ratio. A line-shape analysis as a function composition that, 450\ifmmode^\circ\else\textdegree\fi{}C, exists range ${\mathrm{Cu}}_{1.00}$${\mathrm{In}}_{1.00}$${\mathrm{S}}_{2}$ ${\mathrm{Cu}}_{0.85}$${\mathrm{In}}_{1.05}$${\mathrm{S}}_{2}$. specimens with [Cu]/[In]g1, ${\mathrm{Cu}}_{2}$S contributes signal. separate study ${\mathrm{Cu}}_{2}$S, hexagonal-to-cubic transformation 440\ifmmode^\circ\else\textdegree\fi{}C. activation energy for cubic 0.15 eV. phase-transformation temperatures $\mathrm{CuIn}{X}_{2}$ compounds (where $X$ group-VI element) determined by differential thermal analysis. previously unnoticed found 665\ifmmode^\circ\else\textdegree\fi{}C. Finally, quadrupole coupling constant ${\ensuremath{\chi}}_{q}$ ($^{63}\mathrm{Cu}$) number $\mathrm{Cu}Z{X}_{2}$ $Z$ group-III shown be linear tetragonal distortion parameter $\ensuremath{\delta}=2\ensuremath{-}\frac{c}{a}$ $|{\ensuremath{\chi}}_{q}|=1.50+90\ensuremath{\delta}$ MHz. value $\ensuremath{\delta}=0$ same order magnitude result simple model point charge lattice.