Devil's staircase of odd-number charge order modulations in divalent β -vanadium bronzes under pressure
Devil's staircase of odd-number charge order modulations in divalent β -vanadium bronzes under pressure
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压力下二价β-钒青铜中奇数电荷顺序调制的魔鬼阶梯
DOI：
10.1103/physrevb.97.125138
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发表时间：
2018
影响因子：
3.7
通讯作者：
Y. Ueda
中科院分区：
文献类型：
--
作者：
T. Yamauchi;H. Ueda;K. Ohwada;H. Nakao;Y. Ueda
准一维（q1D）导体（Li， Na和Ag）的一个共同特征是电荷有序（CO），即环境压力下的基态（GS），和超导（SC）相，即高压下的GS，相互竞争。我们探索了双价钒青铜（Ca， Sr和Pb）的高压性质，它们是阳离子化学计量精细控制的单晶/粉末样品，并发现SC相的缺失。然而，在这些观测中，我们观察到巨大的和新颖的相变，一种“魔鬼阶梯”型相变在电荷有序（CO）相。在这个魔鬼阶梯中，最令人惊讶的发现是，许多CO相的所有电荷调制矢量都可以表示为沿轴的原始晶格平移矢量乘以几个奇数。这一发现确实证明了电荷自由度与晶体对称之间的相互作用。我们提出了两种可能的机制来解释这种现象：这些化合物中两个子系统之间的“自电荷转移（载流子再分配）”和朗道相变理论中讨论的“顺序对称还原”。Inwe还发现相图在外观上相似，但在细节上不同。魔鬼的楼梯也被观察到，但它是一个不完整的。此外，其中的电荷调制矢量比中短。在环境压力下，在0.5 GPa以上的50 K左右，观察到压力诱导的反铁磁有序。利用这两种机制，我们还解释了在各种电磁状态下观察到的所有化学计量二价钒青铜的整体高压性质。此外，我们还讨论了压力下SC相存在/不存在的可能关键。
A common characteristic of quasi-one-dimensional (q1D) conductors= Li, Na, and Ag) is that the charge ordering (CO), the ground state (GS) at ambient pressure, and the superconducting (SC) phases, the GS under high pressure, are competing with each other. We have explored high-pressure properties of divalent-vanadium bronzes,= Ca, Sr, and Pb), which are-cation stoichiometry finely controlled single-crystal/powder samples, and found the absence of the SC phase. In these observations, however, we observed enormous and novel phase transitions, a kind of “devil's staircase”-type phase transitions in the charge ordering (CO) phases. The most surprising discovery in this devil's staircase, which was found mainly in, is that all the charge modulation vectors of many kinds of CO phases can be represented as a primitive lattice translation vector along theaxis multiplied by several odd numbers. This discovery surely demonstrates interplay between the charge degree freedom and the crystallographic symmetry. We propose two possible mechanisms to explain this phenomenon: “self-charge transfer (carrier redistribution)” between the two subsystems in these compounds and “sequential symmetry reduction” that was discussed in Landau theory of phase transitions. Inwe also found aphase diagram similar in outlook but different in detail. The devil's staircase was also observed but it is an incomplete one. Furthermore, the charge modulation vectors in it are shorter than those in. In, which hasnoCO phase at ambient pressure, the pressure-induced antiferromagnetic ordering was observed at around 50 K above 0.5 GPa. Using these two kinds of mechanisms, we also explain the global high-pressure properties in all the stoichiometric divalent-vanadium bronzes, which were observed as a wide variety of electromagnetic states. In addition, we also discuss a possible key for the presence/absence of the SC phase under pressure.
β-Pb_0.33V_20_5 中的压力感应磁排序
DOI：
--
发表时间：
2007
期刊：
J. Phys. Soc. Jpn. Suppl. A 76
影响因子：
--
作者：
M.Mimura;T.Miyaji and I.Ohnishi;T. Yamauchi
通讯作者：
T. Yamauchi
准一维导体β-Na_<0.33>V_2O5的局部磁化率和电子结构：单晶中的51V NMR研究
DOI：
--
发表时间：
2006
期刊：
Phys. Rev. B 73
影响因子：
--
作者：
T.Suzuki;I.Yamauchi;M.Itoh;T.Yamauchi;Y.Ueda
通讯作者：
Y.Ueda
β-Sr_<0.33>V_2O_5压力下的多重基态竞争
DOI：
--
发表时间：
2007
期刊：
Phys.Rev.B 75
影响因子：
--
作者：
T.Yamauchi;H.Ueda;J.Yamaura;Y.Ueda
通讯作者：
Y.Ueda