Linear and Nonlinear Two-Terminal Spin-Valve Effect from Chirality-Induced Spin Selectivity

Abstract

Various mechanisms of electrical generation of spin polarization in nonmagnetic materials have been a subject of broad interest for their underlying physics and device potential in spintronics. One such scheme is chirality-induced spin selectivity (CISS), with which structural chirality leads to different electric conductivities for electrons of opposite spins. The resulting effect of spin filtering has been reported for a number of chiral molecules assembled on different surfaces. However, the microscopic origin and transport mechanisms remain controversial. In particular, the fundamental Onsager relation was argued to preclude linear-response detection of CISS by a ferromagnet. Here, we report definitive observation of CISS-induced magnetoconductance in vertical heterojunctions of (Ga,Mn)As/AHPA-L molecules/Au, directly verifying spin filtering by the AHPA-L molecules via spin detection by the (Ga,Mn)As. The pronounced and robust magnetoconductance signals resulting from the use of a magnetic semiconductor enable a rigorous examination of its bias dependence, which shows both linear-and nonlinear-response components. The definitive identification of the linear-response CISS-induced two-terminal spin-valve effect places an important constraint for a viable theory of CISS and its device manifestations. The results present a promising route to spin injection and detection in semiconductors without using any magnetic material.

Theory of Chirality Induced Spin Selectivity: Progress and Challenges

“…While at a theoretical level the connection is largely unexplored, most recent transport measurements on microscopic samples have already been interpreted in terms of a linear CISS effect, see refs. [111–113]. How this interpretation can be reconciled with the Onsager‐symmetry constraint remains to be seen.…”

Spin‐Dependent Charge Transport in 1D Chiral Hybrid Lead‐Bromide Perovskite with High Stability

“…), chiral HOIPs show greater potential in spintronic devices due to the tunable band structure and outstanding optoelectronic properties. [26][27][28] Previous studies have achieved spin-dependent charge transport in 2D chiral perovskites, methylbenzylammonium lead iodide (MBA) 2 PbI 4 , [29] tin iodide (MBA) 2 SnI 4 , or alloyed Pb-Sn perovskites. [30] Additionally, the chiral iodide HOIP also shows potential in magneto-optical detection based on CISS effect.…”

Linear-response magnetoresistance effects in chiral systems

“…Building on this, we predicted that any magnetization-reversal-induced MR percentage that may emerge beyond linear response must first appear linear in bias, just as in the electrical magneto-chiral effect [24,26]. These results were supported by further theoretical analyses [22,27], but still intrigued much discussion since it cannot fully explain experimental observations [9,28,29].…”

“…It promises novel applications such as using chiral materials for information technologies (spintronics) [2] and using spintronic techniques for chemistry and biology [3]. However, despite intensive experimental and theoretical investigations [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], CISS remains poorly understood.…”