Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 30: Focus Session: Young Semiconductor Forum
HL 30.2: Hauptvortrag
Mittwoch, 19. März 2025, 10:00–10:30, H13
Huge Enhancement of the Giant Negative Magnetoresistance with Decreasing Electron Density — •Lina Bockhorn1, Christian Reichl2, Werner Wegscheider2, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — 2Laboratorium für Festkörperphysik, ETH Zürich, Switzerland
Ultra-high mobility two-dimensional electron gases often show a remarkably robust negative magnetoresistance at zero magnetic field. Below 800 mK, this phenomenon divides into two distinct parts [1-4]: a temperature-independent narrow peak around B=0 T, arising from the interplay of smooth disorder and elastic scattering at macroscopic defects [2, 3], and a temperature-dependent giant negative magnetoresistance (GNMR) at higher magnetic fields. The theoretical understanding of the GNMR remains an open question, as it involves several independent parameters in addition to electron-electron interaction possibly leading to hydrodynamic transport effects. To gain insights into the nature of the GNMR, we investigate this effect as a function of electron density at various temperatures and currents. Our results show a significant dependence of GNMR on electron density [4], indicating that variations in scattering potentials [5] are not considered appropriately in theoretical models. [1] L. Bockhorn et al., Phys. Rev. B 83, 113301 (2011). [2] L. Bockhorn et al., Phys. Rev. B 90, 165434 (2014). [3] L. Bockhorn et al., Appl. Phys. Lett. 108, 092103 (2016). [4] L. Bockhorn et al., Phys. Rev. B 109, 205416 (2024). [5] Y. Huang et al., Phys. Rev. Materials 6, L061001 (2022).
Keywords: negative magnetoresistance; high mobility two-dimensional electron gas