新穎量子物質之物理特性研究-超快雷射技術應用於新穎量子物質物理特性之研究

Abstract

在本二年計晝中，我們將延續前面幾年有關利用超快光譜技術量測高溫超導釔鈣鋇銅氧、龐磁 阻鑭鈣錳氧、多鐵稀土族錳氧化物薄膜物理特性的經驗，繼續研究新穎量子物質如強關聯電子系統 氧化物、石墨烯、拓樸絕緣體等材料的超快動力學，以瞭解這些材料的電、磁和光的物理特性。

使用的超快光譜量測系統，包含已建立的時間解析連續超白光激發-光檢測系統、時間解析可調 光激發-光檢測系統、時間解析光激發-兆赫波檢測系統、時間解析磁光科爾效應量測和兆赫波時域光 譜量測等系統。

利用激發-探測實驗，將量測各種量子物質的超快性質與檢測光子能量關係、超快載子與聲子的 弛緩與載子復合等動力行為、導電率動力行為、同調聲子機制、電子能帶結構等。利用時間解析磁 光科爾效應量測系統，將研究新穎量子物質材料的各向異性自旋磁動力行為和進動振盪行為。利用 兆赫波時域光譜量測系統，將研究這些材料的兆赫電磁特性，包含折射率、導電率、介電常數、化 學勢和載子遷移率等。我們亦擬利用已建立的超快雷射材料處理系統，研究這些量子物質經超快雷 射退火和造型處理後，其電、磁、光物理特性，表面或晶體結構之改變。

利用超快光電技術研究這些新穎量子物質的超快光學動力行為，有助於瞭解這些材料的基礎物理 特性和開發新型超高速/高頻電子和光電元件、兆赫波偵測元件、磁電耦I合元件、自旋電子元件和非 線性光學等應用。

In this two-year project, we shall extend our previous experience in ultrafast techniques to investigate the ultrafast dynamics and the electric, magnetic, and optical properties of novel quantum matters such as strongly correlated electron oxides, graphene, topological insulators.

The ultrafast measurement systems will be used in this project include: time-resolved optical(400 nm/800 nm) pump-optical (continuous white spectrum/tunable 720 nm-830nm/400 nm/800 nm) probe systems(OPOP) , time-resolved optical(400 nm/800 nm) pump- THz probe systems(OPTP), THz time domain spectroscopy (TDS), and time-resolved magneto-optic Kerr effect (TR-MOKE) measurement system.

We will use the OPOP and OPTP systems to study the dependence of ultrafast properties on the probe photon energies, the carrier and phonon relaxation processes, the carrier recombination process, the conductivity dynamics, the mechanism of the coherent phonon, and the electronic band structure of these novel quantum matters. We shall use TR-MOKE measurement system to study the anisotropic spin and magnetization dynamics, and the precessional behaviors of these materials. A THz TDS system will be used to study the THz characteristics of these materials, such as refractive index, optical conductivity, dielectric constant, chemical potential, and mobility. Finally, an ultrafast laser deposition and processing system will be used to investigated the effects of ultrafast laser annealing and patterning on the electronic, magnetic, and optical properties, surface morphology, and crystalline structure.

The study of the ultrafast dynamics of these novel quantum matters by ultrafast techniques will help us to understand the new fundamental physics as well as to develop the potentially revolutionary applications for high-speed/high-frequency electronic and optoelectronic devices, terahertz sensors, magnetoelectric coupling devices and nonlinear optical elements.