论文标题
抗铁磁/铁磁半导体中的木 - 双极载体阻力热电器：理论配方和实验证据
Magnon-bipolar carrier drag thermopower in antiferromagnetic/ferromagnetic semiconductors: theoretical formulation and experimental evidence
论文作者
论文摘要
量化的自旋波（称为镁，一种玻色粒的准颗粒）可以通过SD交换相互作用拖动电子或孔，并在常规的扩散热电器上增强热电图。在铁磁和反铁磁金属和退化半导体中都观察到了p型镁拖力热电器。然而，对于固有或N型磁性半导体的报道较少。因此，磁双极载体阻力对热电器的影响尚未得到探索。在这里，基于镁载体相互作用的寿命得出了一种磁双极载体阻力热电器的理论模型。该模型预测，双极载体阻力热电器与载体和镁松弛时间无关。提出了概念验证实验证明，以证实这一预测。我们还通过实验性地报告了N型和内在铁磁半导体中磁载器阻力热电器的观察。 P型抗磁磁MNTE掺杂了不同量的Cr，以产生各种载体浓度的非脱位和N型半导体。 Cr掺杂剂具有供体性质，并由于CR3+氧化状态而产生铁磁 - 抗铁磁簇。热容量测量证实了在掺杂的MNTE中存在少量的。结果表明，由于双极阻力效应，3％-5％CR掺杂的样品的镁拖力型热电图显着降低，并且由于占主导地位的镁电子拖拉热电图，含量为14％和20％CR掺杂的MNTE。
Quantized spin-wave known as magnon, a bosonic quasiparticle, can drag electrons or holes via sd exchange interaction and boost the thermopower over the conventional diffusive thermopower. P-type magnon-drag thermopower has been observed in both ferromagnetic and antiferromagnetic metallic and degenerate semiconductors. However, it has been less reported for intrinsic or n-type magnetic semiconductors; therefore, the impact of magnon-bipolar carrier drag on thermopower has remained unexplored. Here, a theoretical model for magnon-bipolar carrier drag thermopower is derived based on the magnon-carrier interaction lifetimes. The model predicts that the bipolar carrier drag thermopower becomes independent of both the carrier and magnon relaxation times. A proof of concept experiment is presented that confirms this prediction. We also report the observation of magnon-carrier drag thermopower in n-type and intrinsic ferromagnetic semiconductors experimentally. The p-type antiferromagnetic MnTe is doped with different amounts of Cr to produce non-degenerate and n-type semiconductors of various carrier concentrations. Cr dopants have a donor nature and create ferromagnetic-antiferromagnetic clusters due to the Cr3+ oxidation state. Heat capacity measurements confirm the presence of magnons in Cr-doped MnTe. It is shown that the magnon-drag thermopower is significantly reduced for 3%-5% Cr-doped samples due to bipolar drag effects and becomes negative for 14% and 20% Cr-doped MnTe due to dominant magnon-electron drag thermopower.
