複雜自適性物質---子計畫三：量子體物理的探討

Abstract

二十世紀的凝態物理有兩個源自Landau 的基石：費米液體模型與相變 中有序參數的觀念。量子體是指某些物質，可能Landau 的範式無法適用 於其中。這些新物質可能具有強關聯電子系統或低維度的特性。為了尋找 新物理，我們將研究具上述特徵的系統。實驗上，我們將著重對理論模型 的嚴格驗證與以更深入的觀察和新材料的開發刺激新理論的出現。同樣重 要的，我們想在實驗上回答一個基礎的問題：費米液體模型與準粒子的觀 念真的不再具普遍性嗎？我們也將探討奈米尺度下，量子體的物理特性是 否保持不變，這個有趣的問題也具有重要的潛在應用性。我們提議的研究 方法包括：在0.35 K~400 K 溫區與高磁場下〈至9 T〉的電性傳輸、熱電 力、熱傳導、電介質係數與磁性測量，變溫X 光吸收光譜〈XANES 和 EXAFS〉，比熱實驗，STM，飛秒雷射光譜等。

Quantum matters physics is physics beyond Landau』s two paradigms: the idea of Fermi liquid and quasiparticles, and the concept of the order parameter in phase transitions. Possible quantum matters could exist in the strongly correlated electron systems and/or low dimensional systems. Consequently, we proposal to study cobaltates, cuprates, manganites, and other new materials. Looking for new physics, attention will be paid to the critical tests of the theoretical predictions, the new experimental observations stimulating further developments of theory, as well as whether the model of Fermi liquid indeed fails in these matters. The physical properties of the quantum matters on the nano scale will also be studied, which could lead to profound technology impacts. The methodology of this project involves electrical transport, thermal electric power, thermal conductivity, dielectric constant and magnetic property measurements in the temperature range 0.35~400 K and magnetic fields up to 9 T, temperature variable x-ray absorption spectroscopy (including XANES and EXAFS), specific heat measurements, STM, and femtosecond spectroscopy.