2020 Fiscal Year Final Research Report
Cooperative monopole dynamics in spin ice
| Project/Area Number |
17H04849
|
|---|
| Research Category |
Grant-in-Aid for Young Scientists (A)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Condensed matter physics II
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2017-04-01 – 2021-03-31
|
| Keywords | スピンアイス / カゴメアイス / 量子スピンアイス / 磁気モノポール / Dy2Ti2O7 / Tb2Ti2O7 |
|---|
| Outline of Final Research Achievements |
An elementary excitation in spin ice shows similar properties of the Dirac monopole that interacts with magnetic Coulomb forces. However, it has not been clarified whether the excitation manifests itself as a magnetic relaxation phenomenon or it can behave like a quasiparticle with a cooperative phenomenon. In this study, we have focused on Dy2Ti2O7and Tb2Ti2O7, and studied novel elementary excitation phenomena in spin ice, such as two-dimensional (2D) monopoles and quantum monopoles. We have found that the ac frequency dependent magnetic susceptibility in the 2D spin ice of Dy2Ti2O7 shows a single scaling form, which can be understood in terms of the dynamical scaling low for 2D Coulomb gas system (Phys. Rev. B 90, 144428 (2014).). We also realized for Tb2Ti2O7 that the behavior of the monopole characterized by a quantum spin ice could be clarified as information on thermal excitation. These studies shed light on the novel dynamics of monopole phenomenon in condensed matter physics.
|
| Free Research Field |
低温物性実験、中性子散乱実験、結晶合成
|
| Academic Significance and Societal Importance of the Research Achievements |
本研究の結果、モノポールの2次元ダイナミクスは2次元XYモデルの理想的な実験系であること、そしてモノポール対間の相関長が重要な物理量であることが明らかになった。これは、スピンアイスにおけるモノポールのダイナミクスに関する新しい実験事実であり、固体凝縮相における新奇な素励起の実態を明らかにした点で学術的に非常に重要な成果である。また、Tb2Ti2O7でも量子スピンアイスを特徴づけるモノポールの振る舞いを熱励起の情報として明らかにでき、今後の研究につながる研究成果をあげることができた。
|
