Generalized density-of-states and anharmonicity of the low-energy phonon bands from coherent inelastic neutron scattering response in the pyrochlore osmates A Os 2 O 6 ( A = K , Rb , Cs )
Generalized density-of-states and anharmonicity of the low-energy phonon bands from coherent inelastic neutron scattering response in the pyrochlore osmates A Os 2 O 6 ( A = K , Rb , Cs )
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烧绿石锇酸 A Os 2 O 6 ( A = K , Rb , Cs ) 中相干非弹性中子散射响应的低能声子带的广义态密度和非谐性
DOI：
10.1103/physrevb.78.104307
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发表时间：
2008
影响因子：
3.7
通讯作者：
Y. Nagao
中科院分区：
文献类型：
--
作者：
H. Mutka;M. Koza;Mark R. Johnson;Z. Hiroi;J. Yamaura;Y. Nagao
Inelastic neutron scattering on powder samples has been employed to investigate the lattice dynamics of alkali-metal osmates. We have obtained the neutron weighted generalized phonon density-of-states from momentum-transfer averaged coherent inelastic response. We have paid special attention to the low-energy modes that have been assigned to the Einstein term of the lattice specific heat and from which a ``rattling'' behavior of the alkali atoms has been inferred. In all of the three compounds our results reveal a split band with two prominent peaks in the low-energy range associated with the vibrational modes of $A$ atoms. The temperature dependence of these bands has been followed in the range from $1.5\text{ }\text{K}lTl300\text{ }\text{K}$. The strongest temperature effect is visible in the case of ${\text{KOs}}_{2}{\text{O}}_{6}$, the split band peaking at $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}5.5\text{ }\text{meV}$, and 6.8 meV at $T=300\text{ }\text{K}$ softens on cooling resulting in a main band at about $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}3.4\text{ }\text{meV}$ at $T\ensuremath{\lesssim}50\text{ }\text{K}$, while a smaller softening of $\ensuremath{\Delta}(\ensuremath{\hbar}\ensuremath{\omega})l1\text{ }\text{meV}$ is seen in the other two compounds. In agreement with earlier work the temperature dependent modifications of the phonon spectrum can be attributed to the weak potential felt by the $A$ atom in the oversized cage where it is located. At low $T$ the characteristic energies for each of the compounds are well correlated with the specific-heat observations published earlier. The powder averaged phonon response shows $Q$ dependence indicating coherent coupling of the alkali atom vibrations with the rest of the lattice.
Inelastic neutron scattering on powder samples has been employed to investigate the lattice dynamics of alkali-metal osmates. We have obtained the neutron weighted generalized phonon density-of-states from momentum-transfer averaged coherent inelastic response. We have paid special attention to the low-energy modes that have been assigned to the Einstein term of the lattice specific heat and from which a ``rattling'' behavior of the alkali atoms has been inferred. In all of the three compounds our results reveal a split band with two prominent peaks in the low-energy range associated with the vibrational modes of $A$ atoms. The temperature dependence of these bands has been followed in the range from $1.5\text{ }\text{K}lTl300\text{ }\text{K}$. The strongest temperature effect is visible in the case of ${\text{KOs}}_{2}{\text{O}}_{6}$, the split band peaking at $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}5.5\text{ }\text{meV}$, and 6.8 meV at $T=300\text{ }\text{K}$ softens on cooling resulting in a main band at about $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}3.4\text{ }\text{meV}$ at $T\ensuremath{\lesssim}50\text{ }\text{K}$, while a smaller softening of $\ensuremath{\Delta}(\ensuremath{\hbar}\ensuremath{\omega})l1\text{ }\text{meV}$ is seen in the other two compounds. In agreement with earlier work the temperature dependent modifications of the phonon spectrum can be attributed to the weak potential felt by the $A$ atom in the oversized cage where it is located. At low $T$ the characteristic energies for each of the compounds are well correlated with the specific-heat observations published earlier. The powder averaged phonon response shows $Q$ dependence indicating coherent coupling of the alkali atom vibrations with the rest of the lattice.
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影响因子：
8.6
作者：
T. Dahm;K. Ueda
通讯作者：
T. Dahm;K. Ueda
响声声子对β-烧绿石KOs_2O_6超导体准粒子激发动力学的影响
DOI：
--
发表时间：
2007
期刊：
Physical Review Letters 98
影响因子：
--
作者：
Y.Shimono;T.Shibauchi;Y.Kasahara;T.Kato;K.Hashimoto;Y.Matsuda;J.Yamaura;Y.Nagao;Z.Hiroi
通讯作者：
Z.Hiroi
β-烧绿石氧化物超导体CsOs_2O_6和RbOs_2O_6的比热
DOI：
--
发表时间：
2005
期刊：
J.Phys.Soc.Jpn. 74
影响因子：
--
作者：
H.Kambara;T.Matsui;Y.Niimi;H.Fukuyama;Z.Hiroi
通讯作者：
Z.Hiroi
β-烧绿石氧化物超导体KOs_2O_6比热的第二个异常
DOI：
--
发表时间：
2005
期刊：
J.Phys.Soc.Jpn. 4
影响因子：
--
作者：
Z.Hiroi;S.Yonezawa;J.Yamaura;T.Muramatsu;Y.Muraoka
通讯作者：
Y.Muraoka
幽绿石超导体 KOs2O6 的上临界场异常高，低于增强的顺磁极限
DOI：
--
发表时间：
2006
期刊：
Physical Review 220506(1-4)
影响因子：
--
作者：
T. Shibauchi;L. Krusin-Elbaum;Y. Kasahara;Y. Shimono;Y. Matsuda;R. D. McDonald;C. H. Mielke;S. Yonezawa;Z. Hiroi;M. Arai;T. Kita;G. Blatter;and M. Sigrist
通讯作者：
and M. Sigrist