[19p-W241-2~12] 10.4 Semiconductors, organic, optical, and quantum spintronics

[19p-W241-2] Investigation of Large Thermopower of Ga1-xMn_xAs

〇KAZUYA ARAKAWA¹, YUKI TAKETOMI¹, SHIGERU KAKU¹, JYUNJI YOSHINO¹ (1.Tokyo tech Dept. phys)

Keywords:dilute magnetic semiconductor,thermopower,phonon drag

We remarked large thermopower of GaMnAs in the low temperature region in this study. Normally, thermopower of semiconductors is large because of phonon drag while high carrier density causes decrease of it due to density saturation effect. However GaMnAs shows high thermopower about 1mV/K despite its high carrier density of 10²⁰/cm³ orders. We aimed to examine this unique behavior by comparing experimentally measured thermopower of Ga_1-xMn_xAs with numerical calculated thermopower.We used phonon drag thermoelectric theory as well as conventional diffusion thermopower theory for calculations of Ga_1-xMn_xAs thermopower.Ga_1-xMn_xAs samples were grown by low-temperature molecular-beam epitaxy changing Mn and carrier density. To investigate the cause of the large thermopower of Ga_1-xMn_xAs may help to reveal the electronic structure because thermopower reflect the detailed electronic structure.