发表机构
Instituto de Física da Universidade de São Paulo; Institute of Semiconductor Physics; Novosibirsk State University（圣保罗大学物理研究所; 半导体物理研究所; 新西伯利亚国立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究探讨无隙HgTe量子阱中混合三组分等离子体的电荷输运，发现电阻近似按$T^2$增加，归因于重空穴使化学势钉扎于狄拉克点之上，轻电子与重空穴的短程相互作用主导输运，为多组分系统相互作用输运提供了新平台。
AI 中文摘要
二维系统中的电子-空穴等离子体主要在两种极限情况下被研究：具有抛物线能带的简并半金属，以及诸如石墨烯的非简并对称狄拉克系统。这里我们研究了在无隙HgTe量子阱中实现的一种不同状态：一种多组分等离子体，其中无质量狄拉克载流子与来自横向价带谷的热激活重空穴共存。在电荷中性点附近，电阻近似按$T^2$增加，这与对称狄拉克等离子体所预期的几乎与温度无关的电阻率形成鲜明对比。我们表明，一旦重空穴被填充，电荷中性将化学势钉扎在狄拉克点之上，使得狄拉克电子保持适度简并，而重空穴保持非简并并服从玻尔兹曼统计。因此，轻电子几乎弹性地散射重空穴，允许对粒子间输运进行弛豫时间处理。利用自洽能带结构计算得到的载流子密度，我们在弱无序极限下用短程电子-空穴相互作用重现了数据，此时电导率按$T^{-2}$标度，超额电阻率与重空穴密度成正比。相反，未屏蔽的库仑相互作用将给出与温度无关的电导率。提取的相互作用幅度处于预期的库仑尺度。这些结果确立了近临界HgTe量子阱作为结合简并无质量和非简并重质量载流子的多组分系统中相互作用驱动输运的平台。
英文摘要
Electron--hole plasma in two-dimensional systems has mainly been studied in two limiting cases: degenerate semimetals with parabolic bands and nondegenerate symmetric Dirac systems such as graphene. Here we investigate a different regime realized in a gapless HgTe quantum well: a multicomponent plasma where massless Dirac carriers coexist with thermally activated heavy holes from lateral valence-band valleys. Near charge neutrality, the resistance increases approximately as $T^2$, in sharp contrast to the nearly temperature-independent resistivity expected for a symmetric Dirac plasma. We show that once heavy holes are populated, charge neutrality pins the chemical potential above the Dirac point, leaving the Dirac electrons moderately degenerate while the heavy holes remain nondegenerate and obey Boltzmann statistics. The light electrons therefore scatter almost elastically from the heavy holes, allowing a relaxation-time treatment of interparticle transport. Using carrier densities from self-consistent band-structure calculations, we reproduce the data with a short-range electron--hole interaction in the weakly disordered limit, for which the conductivity scales as $T^{-2}$ and the excess resistivity is proportional to the heavy-hole density. In contrast, an unscreened Coulomb interaction would give a temperature-independent conductivity. The extracted interaction amplitude is of the expected Coulomb scale. These results establish near-critical HgTe quantum wells as a platform for interaction-driven transport in multicomponent systems combining degenerate massless and nondegenerate massive carriers.
Comments15 pages, 6 figures
Journal refPhys. Rev. B 114, 235302 (2026)
