Angular variation of spin-orbit branching ratio in photoelectron spectroscopy

Abstract

The studies having been carried out on the anisotropy of the spin-orbit BR (Branching Ratio) were reviewed. The initial state effect and diffraction effect on the BR anisotropy were studied, and In 4d core level was investigated for In/Si(001) using synchrotron radiation. The angle-scanned PD (Photoelectron Diffraction) and In 4d spin-orbit pair spectra were measured for SD (Single-Domain) and DD (Double-Domain) phase of In/Si(001). Typical angular variations of the BR (4d(sub 5/2)/4d(sub 3/2)) for these surfaces with respect to azimuth angle were shown in a figure. It was found that the change of BR was drastic as a function of the emission angle. The results indicated that the BR anisotropy strongly reflected the local structure of the solid surface by the diffraction effect. It was suggested that the large difference of BR anisotropy included the diffraction effect induced by a large difference of kinetic energy. It was proved that the initial state effect largely contributed to the BR anisotropy from solid surfaces.

スピン-軌道BR(分岐比)の異方性に関するこれまでの研究を概観した。シンクロトロン放射を使ってBR異方性に及ぼす初期状態効果および回折効果を研究し、In/Si(001)についてInの4dコア準位を検討した。In/Si(001)のSD(単一分域)およびDD(複分域)相について、角度走査PD(光電子回折)およびInの4dスピン-軌道対スペクトルを測定した。方位角に対するこれら分域面におけるBR(4d(sub 5/2)/4d(sub 3/2))の代表的角度変化を図に示した。放出角の関数としてBRは大きく変化することが分かった。この結果はBR異方性が回折効果により固体表面の局部構造を強く反映することを示した。BR異方性の大きな差異には運動エネルギーの大きな差が誘発した回折効果を含んでいることを示唆した。初期状態効果が固体表面からのBR異方性に大きく寄与していることが明らかになった。