Two-Dimensional Quantum Properties of Monolayer Helium Three Adsorbed on ZYX Graphite

ZYX石墨吸附单层氦三的二维量子特性

• 批准号: 15340113
• 负责人: FUKUYAMA Hiroshi
• 金额: $ 10.62万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15340113/
• 关键词: quantum fluids; strong correlation; low dimensions; Fermi fluids; nuclear magnetic resonance; frustration; superfluid; nuclear magnetism; 比熱

We investigated strong correlation effects in two-dimensional Fermion systems by measuring hear capacities and magnetization of monolayer ^3He physisorbed on ^4He preplated graphite surfaces. Four distinct regions including so far unknown new quantum fluid phases were observed as a function of areal density, which indicates a rather complicated phase diagram for this system.At low densities (Region-I), the low temperature properties can be described well by the Fermi fluid theory where the quasi-particle effective mass is enhanced by ten times of the bare mass. Upon increasing density towards that (6.9 nm^<-2>) for the 4/7 phase which is commensurate against the underlayer, the behavior of heat capacity and magnetization deviates from the Fermi fluid theory and shows anomalous spin-mass separation like tendency (Region-II). This region should be a new quantum fluid, for which we proposed a hypothesis of the 4/7 phase (Mott localized phase) doped with the zero-point vacancies (holes). With further increasing density, there appears another region where both heat capacity and magnetization do not change appreciably (Region-III). And then above 8.3 nm^<-2> the system undergoes a two-phase coexistence region (Region-IV) between the Region-III and a ferromagnetic phase. Region-III would be also a new quantum fluid with different properties from those of Region-II. It is desired to clarify whether its fluidity comes from the liquid phase promoted to the overlayer or from the 4/7 phase doped with excess particles in the near future.We verified our previous claim of the gapless quantum spin-liquid for the magnetic ground state of the 4/7 phase. Importantly, no gapped behavior was observed at temperatures down to 0.07 mK in the whole density range we studied. This is consistent with the path integral renormalization group calculation for the Hubbard model on a triangular lattice, and would be a general property of the strongly correlated fermions with frustration.

我们通过测量听觉能力和单层的磁化 ^3he物理学的磁化物在 ^4E预先绘制的石墨表面上，研究了二维费米昂系统中的强相关效应。在迄今为止未知的四个不同区域（包括迄今未知的新量子流体阶段）作为面积密度的函数观察到，这表明该系统的相图相当复杂。在低密度（区域I）中，可以通过费米流体理论很好地描述低温特性，其中准颗粒的有效质量可增强裸质量的十倍。在增加密度（6.9 nm^<-2>）的4/7相（相称）与底层相称时，热容量和磁化的行为与费米流体理论偏离，并显示出异常的自旋质量分离趋势（例如区域-II）。该区域应该是一种新的量子流体，为此，我们提出了用零点空位（孔）掺杂的4/7相（Mott局部相）的假设。随着密度的进一步增加，出现了另一个区域，在该区域中，热容量和磁化不会发生明显变化（INAIGH-III）。然后高于8.3 nm^<-2>该系统在区域III和铁磁相之间经历两相共存区域（区域IV）。区域III也将是一种新的量子流体，其特性与区域II的特性不同。希望澄清其流动性是来自液体相位的液相，还是来自不久的将来，从叠加层促进的液相，还是来自与多余颗粒的4/7相。重要的是，在我们研究的整个密度范围内，在温度低至0.07 mk的温度下未观察到间隙行为。这与三角形晶格上哈伯德模型的路径积分重归化组计算一致，并且将是与挫败感密切相关的费米子的一般特性。

项目成果

NMR Measurements of a Possible New Quantum Phase in 2D ^3He

2D ^3He 中可能的新量子相的 NMR 测量

• 发表时间: 2005
• 期刊: Journal of Low Temperature Physics 138
• 作者: Yonehara;Atsunori;D.Tsuji;N.Nakajima et al.;H.Akisato
• 通讯作者: H.Akisato

S.Murakawa: "NMR measurements of 2D^3He adsorbed on ZYX exfoliated graphite"Journal of Low Temperature Physics. 134. 109-114 (2004)

S.Murakawa：“ZYX 膨胀石墨上吸附的 2D^3He 的 NMR 测量”《低温物理学杂志》。

NMR measurements of 2D ^3He adsorbed on ZYX exfoliated graphite

ZYX 膨胀石墨吸附的 2D ^3He 的 NMR 测量

• 发表时间: 2004
• 期刊: Journal of Low Temperature Physics 134
• 作者: J.Kanasaki;K.Tanimura;S.Murakawa
• 通讯作者: S.Murakawa

Heat capacities of the anomalous fluid phase in two-dimensional ^3He

二维 ^3He 反常流体相的热容

• 发表时间: 2005
• 期刊: Journal of Low Temperature Physics 138
• 作者: Y.Matsumoto

Effects of ^4He substitution on low temperature heat capacities of 2D ^3He adsorbed on graphite

^4He取代对石墨吸附二维^3He低温热容的影响

• 发表时间: 2005
• 期刊: Journal of Low Temperature Physics 138
• 作者: Yonehara;Atsunori;D.Tsuji
• 通讯作者: D.Tsuji