Angle-resolved photoemission spectroscopy of Ga(1-x)Mn(x)As

Abstract

The electronic structure of Mn contained in GaAs has been studied using the Angle-Resolved Photoemission Spectroscopy (ARPES) in order to investigate the effect of Mn doping in GaAs and to get the information about interaction between Mn and the host GaAs. The procedure for preparation samples of Ga(1-x)Mn(x)As, and the conditions of photoemission measurement have been outlined. The measured normal emission spectra of GaAs(001) and Ga(1-x)Mn(x)As(001) with x = 0.035 were shown in a figure. In the figure, there appeared a main peak and a satellite peaks along the Gamma-Delta-Chi line. It was found that Mn 3p to 3d resonance clearly occurred in the 50 eV spectrum of Ga(1-x)Mn(x)As, and that the structure of GaAs was overlapped by the Mn 3d contributions. In comparison with GaAs, only the main peak in Ga(1-x)Mn(x)As was shifted towards higher binding energies by 0.1 to 0.2 eV. This behavior was estimated due to the hybridization with the Mn 3d-derived states located a up to 4 eV below E(sub F) (Fermi level). The Mn derived states between E(sub F) and 0.5 eV are probably centered above the valence-band maximum and should be responsible for the metallic conduction in Ga(1-x)Mn(x)As.

GaAs中のMnドーピング効果を検討し、またMnとホストGaAs間の相互作用に関する情報を得るため、GaAs中に包含されているMnの電子構造を角度分解光電子放出分光法(ARPES)を用いて研究した。Ga(1-x)Mn(x)As試料調製手法と光電子放出測定条件の概要を記述した。GaAs(001)およびx=0.035のGa(1-x)Mn(x)As(001)の正常放出スペクトル測定値を図示した。図の中で、Γ-Δ-Χ線に沿って主線ピークと衛線ピークが出現した。Ga(1-x)Mn(x)Asの50eVスペクトルの中にMnの3dに対する3p共鳴が明確に発生していること、およびGaAsの構造がMnの3dの寄与により重なることが分かった。GaAsと比較して、Ga(1-x)Mn(x)Asでは主線ピークだけが0.1?0.2eVづつ高結合エネルギー方向に移動した。この挙動は、E(sub F)(フェルミ準位)以下の4eVまでの間に局在するMnの3d誘導状態との混成作用によるためであると推定した。E(sub F)と0.5eV間のMn誘導状態は価電子帯極大点上方に中心を占め、Ga(1-x)Mn(x)Asにおける金属伝導に対する原因となっていると推測した。