Technical Report of ISSP Ser. A: Number 2675

Abstract

Cyclotron resonance of thermally excited free holes has been observed in synthetic semiconducting diamond at ultra-high magnetic fields up to 150 T generated by the single-turn coil technique with pulsed far-infrared laser radiations of 28,36 and 119 micrometers. Three absorption peaks were observed at and above room temperature for the magnetic fields parallel to the greater than sign 100 less than sign, greater sign 111 less than sign and greater sign 110 less than sign crystallographic directions. The typical value of omega (sub c) tau was as small as two at 40 C even in ultra-high fields. One of the three peaks was observed in the Cyclotron Resonance Inactive (CRI) circular polarization for holes, whilst the other two lines were observed in Cyclotron Resonance Active (CRA) for holes. Assuming that these resonance absorption lines are due to three holes of the valence-bands at the gamma-point, i.e.light-hole, heavy-hole, and split-off-hole, it is able to be concluded that the band dispersion curve for one of the three bands has a negative (electron-like) curvature in some directions.

半導電性合成ダイアモンドの熱的に励起された自由空孔のサイクロトロン共鳴を、単巻きコイル技術により生成した150Tまでの超高磁場中で、28、36および119μmの遠赤外パルスレーザ放射により調べた。〈100〉、〈111〉および〈110〉結晶方向に平行な磁場に対して、室温および室温を超えた温度において、3つの吸収ピークを観測した。ωcτの代表的な値は、超高磁場においても40度Cで、2のような小さな値しか示さなかった。3つのピークのうちの1つは空孔に対してサイクトロン共鳴不活性(CRI)円偏光のかたちで、他の2つは空孔に対してサイクトロン共鳴活性(CRA)のかたちで観測された。これらの共鳴吸収線はガンマ点における価電子帯の3つの空孔によるものであると仮定して、3つのバンドの1つに対するバンド分散曲線はある方向に対して負(電子類似)の曲率を持つことを示した。