Observation of a possible oxygen isotope effect on the effective mass of carriers in YBa2Cu3O6.94.
Observation of a possible oxygen isotope effect on the effective mass of carriers in YBa2Cu3O6.94.
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观察氧同位素对 YBa2Cu3O6.94 中载流子有效质量的可能影响。
DOI：
10.1103/physrevb.51.16487
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Donald E. Morris
中科院分区：
文献类型：
--
作者：
Guo;Donald E. Morris
We have investigated oxygen-isotope effects on the effective mass of carriers ${\mathit{m}}^{\mathrm{*}}$ and carrier concentration ${\mathit{n}}_{\mathit{s}}$ in fine-grained ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{\mathit{y}}$ (y\ensuremath{\approxeq}6.94) using measurements of onset magnetizations in Meissner and mixed states. We find a large negative oxygen-isotope effect on ${\mathit{m}}^{\mathrm{*}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}{\mathit{m}}^{\mathrm{*}}}$=-d ln(m*)/d ln${\mathit{M}}_{\mathrm{O}}$=-0.61\ifmmode\pm\else\textpm\fi{}0.09, and a small oxygen-isotope effect on ${\mathit{n}}_{\mathit{s}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}\mathit{n}}$=-d ln(${\mathit{n}}_{\mathit{s}}$)/d ln${\mathit{M}}_{\mathrm{O}}$=0\ifmmode\pm\else\textpm\fi{}0.13. We also observe a small positive oxygen-isotope effect on ${\mathit{T}}_{\mathit{c}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}}$=-d ln${\mathit{T}}_{\mathit{c}}$/d ln${\mathit{M}}_{\mathrm{O}}$=0.028\ifmmode\pm\else\textpm\fi{}0.002. The large oxygen-isotope effect on ${\mathit{m}}^{\mathrm{*}}$ can be explained as due to the breakdown of the Migdal approximation and/or strong anharmonicity of phonon modes.
We have investigated oxygen-isotope effects on the effective mass of carriers ${\mathit{m}}^{\mathrm{*}}$ and carrier concentration ${\mathit{n}}_{\mathit{s}}$ in fine-grained ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{\mathit{y}}$ (y\ensuremath{\approxeq}6.94) using measurements of onset magnetizations in Meissner and mixed states. We find a large negative oxygen-isotope effect on ${\mathit{m}}^{\mathrm{*}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}{\mathit{m}}^{\mathrm{*}}}$=-d ln(m*)/d ln${\mathit{M}}_{\mathrm{O}}$=-0.61\ifmmode\pm\else\textpm\fi{}0.09, and a small oxygen-isotope effect on ${\mathit{n}}_{\mathit{s}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}\mathit{n}}$=-d ln(${\mathit{n}}_{\mathit{s}}$)/d ln${\mathit{M}}_{\mathrm{O}}$=0\ifmmode\pm\else\textpm\fi{}0.13. We also observe a small positive oxygen-isotope effect on ${\mathit{T}}_{\mathit{c}}$ with an exponent ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{O}}$=-d ln${\mathit{T}}_{\mathit{c}}$/d ln${\mathit{M}}_{\mathrm{O}}$=0.028\ifmmode\pm\else\textpm\fi{}0.002. The large oxygen-isotope effect on ${\mathit{m}}^{\mathrm{*}}$ can be explained as due to the breakdown of the Migdal approximation and/or strong anharmonicity of phonon modes.