Scarpulla M A, Cardozo B L, Farshchi R, Oo W M Hlaing, McCluskey M D, Yu K M, Dubon O D
Department of Materials Science & Engineering, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2005 Nov 11;95(20):207204. doi: 10.1103/PhysRevLett.95.207204. Epub 2005 Nov 8.
We report an energy gap for hole photoexcitation in ferromagnetic Ga(1-x)Mn(x)P that is tunable by Mn concentration (x < or = 0.06) and by compensation with Te donors. For x approximately 0.06, electrical transport is dominated by excitation across this gap above the Curie temperature (TC) of 60 K and by thermally activated hopping below TC. Magnetization measurements reveal a moment of 3.9 +/- 0.4 muB per substitutional Mn while the large anomalous Hall signal demonstrates that the ferromagnetism is carrier mediated. In aggregate these data indicate that ferromagnetic exchange is mediated by holes localized in a Mn-derived band that is detached from the valence band.
我们报道了铁磁体Ga(1-x)Mn(x)P中空穴光激发的能隙，该能隙可通过Mn浓度（x≤0.06）以及用Te施主进行补偿来调节。对于x约为0.06的情况，在高于60K的居里温度（TC）时，电输运主要由跨越该能隙的激发主导，而在TC以下则由热激活跳跃主导。磁化测量表明，每个替代Mn的磁矩为3.9±0.4μB，同时大的反常霍尔信号表明铁磁性是由载流子介导的。总体而言，这些数据表明铁磁交换是由局域在与价带分离的Mn衍生带中的空穴介导的。
