2026/02/13 by Nilay Maji, Subham Mohanty, Pujarani Dehuri +1 · 1 voice
Physics and Astronomy · #cond-mat.other
arxiv published 2026/02/13 · arxiv updated 2026/02/17
Electrical spin injection and transport in silicon are central challenges for realizing semiconductor-based spintronic devices, particularly in p-type Si, where strong spin relaxation and interface effects often suppress detectable spin signals. Here, we report electrical spin injection, accumulation, and transport in lightly doped p-type silicon using the spin-gapless Heusler compound Mn2CoAl as a ferromagnetic spin injector, separated from the p-Si channel by a thin MgO tunnel barrier in a lateral device geometry. Spin transport is systematically investigated through three-terminal (3-T) Hanle and four-terminal (4-T) nonlocal (NL) spin-valve and Hanle measurements. Clear Lorentzian Hanle signals are observed in the 3-T configuration from 5 K up to room temperature, yielding a spin lifetime of ∼0.68 ns at 300 K that increases to ∼4.11 ns at 5 K. Temperature-dependent analysis reveals a weak power-law dependence of the spin lifetime, indicating Bir--Aronov--Pikus--type spin relaxation mechanism. To validate genuine spin transport, NL spin-valve and Hanle measurements were performed, revealing well-defined spin-valve switching and controlled spin precession at 5 K. From NL Hanle fitting, a spin lifetime of ∼5.65 ns and a spin diffusion length of ∼0.82 μm are extracted, confirming diffusive long-range spin transport in the p-Si channel. Although NL signals diminish at elevated temperatures due to reduced interfacial spin polarization and thermal noise, the combined 3-T and 4-T results establish spin-gapless Mn2CoAl as an effective spin injector for p-type silicon. These findings highlight the potential of spin-gapless semiconductors for improving spin injection efficiency and advancing Si-compatible spintronic devices.