FIELD-INDUCED BOSE-EINSTEIN CONDENSATION AND LOCALIZATION OF MAGNONS

场致玻色-爱因斯坦凝聚和磁振子的定位

• 批准号: 13130202
• 负责人: TANAKA Hidekazu
• 金额: $ 65.47万
• 依托单位: TOKYO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13130202/
• 关键词: Magnetism; Experiments for Solid State Physics; Low Temperature Physics; Statistical Mechanics; High Magnetic Field; Quantum Spin Systems; Field-Induced Magnetic Phenomena; Low Dimensional Magnets; スピンギャップ; マグノン; ボース・アインシュタイン凝縮; ESR; 磁場誘起相転移 /

Coupled S=1/2 spin dimer systems such as T1CuCl_3 and KCuCl_3 which we developed undergo novel quantum phase transitions high magnetic fields. These systems often have singlet ground states with excitation gaps. In high magnetic field, one of the triplets whose energy decreases with magnetic field plays an important role. The triplet can hop to neighboring site as a quasi-particle and interact due to the transverse and longitudinal components of the interdimer exchange interaction. The quasi-particle has characteristics of boson and is called magnon. Consequently, the system can be described as interaction boson system, where magnetic field corresponds to the chemical potential. The field-induced antiferromagnetic (AF) ordering occurs when the hopping of magnons is dominant. The ordering can be described as the Bose-Einstein condensation (BEC) of magnons. We have perform various measurements on the field-induced AF ordering in TlCuCl, including magnetization, specific heat, neutron sca … More ttering ultrasonic attenuation, heat-conductivity, thermal expansion measurements. Together with theoretical analysis, we verify that 1 field-induced AF ordering in TlCuCl, is the BEC of magnons. Examples include that experimental critical exponent (1152 for the phase boundary agrees with theoretical φ=3/2, and that theoretical calculation based on the magnon BEC reproduces almost perfectly experimental phase boundary. By means of magnetization and neutron scattering measurements, we observed that spin gap systems T1CuCl_3 and KCuCl_3 undergo phase transition to antiferromagnetic state in hydrostatic pressure. This is the first example the pressure-induced magnetic quantum phase transition from the gapped state to the antiferromagnetic state. We observed magnetization plateau at one-third of the saturation magnetization in Cs2_CuBr_4 that is described as triangular antiferromagnet This plateau is attributed to interplay between spin frustration and quantum fluctuation. We developed many molecular magnet Examples include S=1 and 1/2 mixed spin system BIPNNBNO, S=1 honeycomb lattice antiferromagnet F_2PNNNO, S=1 spin ladder system BIPTENO and S=1/2 alternating antiferromagnetic chain F_5PNN. In BIPTENO, we observed magnetization plateau at one-quarter of the saturation magnetization. This plateau is realized by breaking translational symmetry. We observed the magnetic properties characteristic of the Tomonaga-Luttinger liquid for one-dimensional fermion system. We developed the general theory for electron spin resonance for one-dimensional antiferromagnet. Less

耦合s = 1/2旋转二聚体系统，例如T1CUCL_3和KCUCL_3，我们开发的新型量子相转换会导致高磁场。这些系统通常具有刺激差距的单线基态。在高磁场中，其中一个用磁场降低的三胞胎起着重要作用。三胞胎可以以准粒子的形式跳到相邻的位点，并由于互换相互作用的横向和纵向成分而相互作用。准粒子具有玻色子的特征，称为磁蛋白。因此，该系统可以描述为相互作用的玻色子系统，其中磁场对应于化学电位。当镁的跳跃占主导地位时，现场诱导的抗铁磁（AF）排序发生。该订单可以描述为少量的Bose-Einstein凝结（BEC）。我们已经对TLCUCL中的现场诱导的AF顺序进行了各种测量，包括磁化，比热，中子SCA…更多的超声波衰减，热导率，热膨胀测量值。与理论分析一起，我们验证了TLCUCL中的1个场诱导的AF排序是镁的BEC。 Examples include that experimental critical exponent (1152 for the phase boundary agrees with theoretical φ=3/2, and that theoretical calculation based on the magnon BEC reproduces almost perfectly experimental phase boundary. By means of magnetization and neutron scattering measurements, we observed that spin gap systems T1CuCl_3 and KCuCl_3 undergo phase transition to antiferromagnetic state in hydrostatic pressure. This is the first example the在CS2_CUBR_4中，压力诱导的磁性量子相过渡到抗磁磁状态。 Bipnnbno，s = 1蜂窝晶格抗fiferromagnet f_2pnnno，s = 1个自旋梯子系统bipteno，s = 1/2替代性抗铁磁性链F_5pnn。在Bipteno中，我们在饱和磁化的四分之一处观察到磁化高原。通过破坏翻译对称性来实现该平台。我们观察到了一维费米昂系统的Tomonaga-Luttinger液体的磁性特性。我们开发了一维抗fiferromagnet的电子自旋共振的一般理论。较少的

项目成果

S.Maruyama: "Susceptibility, Magnetization Process and ESR Studies on the Helical Spin System RbCuCl_3"J. Phys. Soc. Jpn.. 70. 859-865 (2001)

S.Maruyama：“螺旋自旋系统RbCuCl_3的磁化率、磁化过程和ESR研究”J。

H.Tanaka: "Magnetic Ordering under High Pressure in Quantum Spin System TlCuCl_3"Physica B. 329-333. 697-698 (2003)

H.Tanaka：“量子自旋系统 TlCuCl_3 中高压下的磁有序”Physica B. 329-333。

Boundary critical phenomena in SU(3) "spin" chain

SU(3)“自旋”链中的边界临界现象

• 发表时间: 2001
• 期刊: J.Phys.A 34
• 作者: K.Suzuki;Y.Hosokoshi;K.Inoue;A.Oosawa;H.Tanaka;I.Affleck
• 通讯作者: I.Affleck

M.Tanaka: "Metal (3d)-organic (2p)-hybrid magnets made of Mn(II) ions with tris(aminoxyl) radicals (R's) as bridging ligands 2D complexes [{Mn(hfac)2}3_R2]"Synth Metals. 122. 463-470 (2001)

M.Tanaka：“由 Mn(II) 离子制成的金属 (3d)-有机 (2p)-混合磁体，并以三(氨氧基)基团 (Rs) 作为桥接配体 2D 配合物 [{Mn(hfac)2}3_R2]”合成

A.Oosawa: "Neutron Inelastic Scattering from the Spin gap System TlCuCl_3"J. Phys. Soc. Jpn. Suppl. A. 70. 166-168 (2001)

A.Oosawa：“来自自旋间隙系统 TlCuCl_3 的中子非弹性散射”J。