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arXiv 1702.05082cond-mat.str-el
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空穴掺杂BaMn $_{2}$ As $_{2}$中金属-绝缘体相变的强反铁磁自旋波

Robust antiferromagnetic spin waves across the metal-insulator transition in hole-doped BaMn$_{2}$As$_{2}$

M. Ramazanoglu, A. Sapkota, Abhishek Pandey, J. Lamsal, D. L. Abernathy, J. L. Niedziela, M. B. Stone, A. Kreyssig, A. I. Goldman, D. C. Johnston, R. J. McQueeney

摘要:

BaMn $_{2}$ As $_{2}$是一种反铁磁绝缘体,其中通过用K取代Ba而在空穴掺杂时发生金属-绝缘体转变。金属-绝缘体转变仅引起Néel温度($T_\mathrm{N}$)和有序矩的小抑制,表明掺杂空穴与Mn自旋系统的弱相互作用。对Ba $_{1-x}$ K $_{x}$ Mn $_{2}$ As $_{2}$(其中$x=$为0、0.125和0.25)三种不同的粉末样品进行了粉末非弹性中子散射测量,以研究空穴掺杂和金属化对这些化合物的自旋动力学的影响。我们比较中子强度的线性自旋波理论近似的$J_{1}-J_{2}-J_{c}$海森堡模型。空穴掺杂被发现引入交换能和自旋间隙只有很小的修改。在交换常数中观察到的变化与掺杂时$T_\mathrm{N}$的小下降一致。

英文摘要:

BaMn$_{2}$As$_{2}$ is an antiferromagnetic insulator where a metal-insulator transition occurs with hole doping via the substitution of Ba with K. The metal-insulator transition causes only a small suppression of the Néel temperature ($T_\mathrm{N}$) and the ordered moment, suggesting that doped holes interact weakly with the Mn spin system. Powder inelastic neutron scattering measurements were performed on three different powder samples of Ba$_{1-x}$K$_{x}$Mn$_{2}$As$_{2}$ with $x=$0, 0.125 and 0.25 to study the effect of hole doping and metallization on the spin dynamics of these compounds. We compare the neutron intensities to a linear spin wave theory approximation to the $J_{1}-J_{2}-J_{c}$ Heisenberg model. Hole doping is found to introduce only minor modifications to the exchange energies and spin gap. The changes observed in the exchange constants are consistent with the small drop of $T_\mathrm{N}$ with doping.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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