C. A. Lozano | Search arXiv

arXiv2026

High-mobility spin transport mediated by indirect excitons in a van der Waals heterostructure

Efficient spin transport with high spin mobility is of both fundamental and practical significance for spintronics. Spin can be transferred by moving particles. However, particle scattering limits spin transfer and prevents high spin mobilities. In this work, we study the kinetics of spin transport mediated by a quantum system of indirect excitons (IXs) in a van der Waals heterostructure composed of atomically thin transition-metal dichalcogenides (TMDs). This spin transfer mechanism allows for the realization of efficient spin transport characterized by a high spin mobility reaching 10$^5$ cm$^2$/(eV$\cdot$s), which is orders of magnitude higher than that achieved via standard diffusive spin transport in TMD materials. The suppression of IX scattering enables high-mobility spin transport.

cond-mat.mes-hall↗

arXiv2026

Transport kinetics in excitonic Mott insulator

Indirect excitons (IXs) in a periodic moiré potential in a van der Waals heterostructure form an experimental platform for exploring Bose-Hubbard physics, including the superfluid state and the Mott insulator state. The realization of these collective states requires low-disorder materials. In particular, the localization due to the Mott insulator must be distinguished from disorder-induced localization. We studied the transport kinetics of IXs in a MoSe$_2$/WSe$_2$ van der Waals heterostructure with an anomalously high IX mobility, consistent with superfluidity. This high-mobility transport demonstrates that disorder-induced localization is negligible. We found a remarkable suppression of this efficient IX transport, directly indicating the Mott insulator. As the IX density increases during the excitation pulse, the IX cloud initially expands and then contracts upon entering the Mott insulator phase. The emergence of IX cloud contraction is accompanied by a peak in the IX spatial distribution at the origin. Our simulations reproduce the observed non-monotonic IX transport kinetics, including the temporal expansion and contraction of the IX cloud, as well as the peak in its spatial distribution.

cond-mat.mes-hall↗