Light-induced hysteresis of electronic polarization in antiferromagnet FePS3
Authors:
Kyung Ik Sim,
Byung Cheol Park,
Taesoo Kim,
Byeong Wook Cho,
Jae Hoon Kim,
Eun-Mi Choi,
Young Hee Lee
Abstract:
Research on manipulating materials using light has garnered significant interest, yet examples of controlling electronic polarization in magnetic materials remain scarce. Here, we demonstrate the hysteresis of electronic polarization in the antiferromagnetic semiconductor FePS3 via light. Below the Néel temperature, we observe linear dichroism (i.e., optical anisotropy) without structural symmetry…
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Research on manipulating materials using light has garnered significant interest, yet examples of controlling electronic polarization in magnetic materials remain scarce. Here, we demonstrate the hysteresis of electronic polarization in the antiferromagnetic semiconductor FePS3 via light. Below the Néel temperature, we observe linear dichroism (i.e., optical anisotropy) without structural symmetry breaking. Light-induced net polarization aligns along the a-axis (zigzag direction) at 1.6 eV due to the dipolar polarization and along the b-axis (armchair direction) at 2.0 eV due to the combined effects of dipolar and octupolar polarizations, resulting from charge transfer from the armchair to the zigzag direction by light. Unexpected hysteresis of the electronic polarization occurs at 2.0 eV due to the octupolar polarization, in contrast to the absence of such hysteresis at 1.6 eV. We attribute this to a symmetry breaking of the light-induced phase of FePS3 involving electronic polarization within the spin lattice. This study suggests a new mechanism for generating and controlling electronic polarization in magnetic materials using light, with implications for future device applications.
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Submitted 2 December, 2024;
originally announced December 2024.
Modulating spin-valley relaxation in WSe$_2$ with variable thickness VOPc layers
Authors:
Daphné Lubert-Perquel,
Byeong Wook Cho,
Alan J. Philips,
Young Hee Lee,
Jeffrey L. Blackburn,
Justin C. Johnson
Abstract:
Combining the synthetic tunability of molecular compounds with the optical selection rules of transition metal dichalcogenides (TMDC) that derive from spin-valley coupling could provide interesting opportunities for the readout of quantum information. However, little is known about the electronic and spin interactions at such interfaces and the influence on spin-valley relaxation. In this work, va…
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Combining the synthetic tunability of molecular compounds with the optical selection rules of transition metal dichalcogenides (TMDC) that derive from spin-valley coupling could provide interesting opportunities for the readout of quantum information. However, little is known about the electronic and spin interactions at such interfaces and the influence on spin-valley relaxation. In this work, vanadyl phthalocyanine (VOPc) molecular layers are thermally evaporated on WSe$_2$ to explore the effect of molecular layer thickness on excited-state spin-valley polarization. The thinnest molecular layer supports an interfacial state which destroys the spin-valley polarization almost instantaneously, whereas a thicker molecular layer results in longer-lived spin-valley polarization than the WSe$_2$ monolayer alone. The mechanism appears to involve a tightly-bound species at the molecule/TMDC interface that strengthens exchange interactions and is largely avoided in thicker VOPc layers that isolate electrons from WSe$_2$ holes.
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Submitted 9 August, 2024; v1 submitted 10 October, 2023;
originally announced October 2023.