摘要: | 在本計劃中,我們預計研究經由能譜、磁性、電導和熱力學測量所顯現如與其 他有序狀態共存的超導、微弱的低能量能譜強度、依循線性Dirac色散關係電子 的量子霍爾效應等等系統的奇異電子狀態。我們計劃探討的材料包含銅氧化物高 溫超導體、過渡金屬二元硫屬化合物、以塊材和接面形式存在的過渡金屬化合物 以及石墨單層片。此計劃在以數值和解析的方法研究簡單模型,而達到至少定性 上瞭解這些現象為目的。 本計劃的大部分,乃是過去三年強調理論研究和實驗高度配合計劃之延續。實 際上,我們已經對本計劃提出的某些部分–例如,連結d-配對波超導態的雜質 散射效應與銅氧高溫超導體的掃瞄穿隧能譜測量的結果,以及(運用具超對稱性 質的量子力學描述方法)來連接雙石墨單層片的電子結構與最近的光發射能譜的 觀察- 展開了研究,而且已有了一些進展。本計劃的完成將有助於對這些複雜電 子系統有比現今更完整的瞭解,並且可能導致具有新穎性質性材料的開發。 We, in this project, plan to investigate electron systems showing anomalous electronic states, like superconductivity (SC) coexisting with other ordered states, weak low-energy spectral weight, quantum Hall effects for electrons following linear, Dirac like dispersion, and so on as revealed by spectroscopy, magnetic, transport and thermodynamic measurements. The materials we intend to study include high Tc cuprate superconductors, transition metal dichalcogenides, transition metal oxides in the bulk or in the junction form and graphene. We aim to understand the phenomena qualitatively, at least, by applying numerical and analytic approaches on simple models. A large part of this project is a continuation of our previous one carried out in the last three years, with strong interplay between our theoretical study and experiments. Some of the project- for example, relating impurity scattering effects on the d-wave SC with scanning tunneling spectroscopy results on high Tc cuprate superconductors, and connecting the electronic band structures of the bi-layer graphene (in terms of supersymmetric quantum mechanical formulation) with the very recent photoemission observation- proposed here have actually started and have made partial progress. The completion of this project shall facilitate a more comprehensive understanding of these complex electron systems than we have now and may then lead to the development of materials with novel properties. |