The Hidden Cost of Alloying: Disorder-Driven Transport Collapse in TMDs

@misc{pisarra2026hidden,
  title = {{The Hidden Cost of Alloying: Disorder-Driven Transport Collapse in TMDs}},
  author = {Michele Pisarra and Clara Rebanal and Enrique Arévalo Rodríguez and Marc Meléndez and Elena Blundo and Giacomo Amadore and Jonathan J. Finley and Fabián Calleja and Marc G. Cuxart and Jesús Álvarez and Ma-ría José Capitán and Fernando J. Urbanos and Julia García Pérez and Ramón Bernardo Gavito and Daniel Granados and Ji Dai and Massimo Tallarida and Antonello Sindona and Fernando Martín and Ferry Prins and Iolanda Di Bernardo and Amadeo L. Vázquez de Parga},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.08597},
  eprint = {2609.08597},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.08597},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - The Hidden Cost of Alloying: Disorder-Driven Transport Collapse in TMDs
AU  - Michele Pisarra
AU  - Clara Rebanal
AU  - Enrique Arévalo Rodríguez
AU  - Marc Meléndez
AU  - Elena Blundo
AU  - Giacomo Amadore
AU  - Jonathan J. Finley
AU  - Fabián Calleja
AU  - Marc G. Cuxart
AU  - Jesús Álvarez
AU  - Ma-ría José Capitán
AU  - Fernando J. Urbanos
AU  - Julia García Pérez
AU  - Ramón Bernardo Gavito
AU  - Daniel Granados
AU  - Ji Dai
AU  - Massimo Tallarida
AU  - Antonello Sindona
AU  - Fernando Martín
AU  - Ferry Prins
AU  - Iolanda Di Bernardo
AU  - Amadeo L. Vázquez de Parga
PY  - 2026
DA  - 2026/09/08
PB  - arXiv
DO  - 10.48550/arxiv.2609.08597
UR  - https://arxiv.org/abs/2609.08597
AB  - Alloying in two dimensional semiconductors is widely used to tune bandgaps, yet its implications for charge and energy transport remain poorly understood. Here, we investigate MoS2xSe2(1-x) alloys as a model system to study the interplay between composition, thickness, and disorder. Optical transitions and valence band dispersions evolve continuously with both stoichiometry and number of layers, with negligible bandgap bowing and a composition dependent attenuation of thickness driven renormalization. In contrast, time resolved spatial mapping of photoexcited carriers reveals a pronounced and asymmetric collapse of carrier diffusivity at intermediate compositions, which cannot be accounted for by changes in effective mass or band alignment, and instead emerges from strong real space fluctuations in the local energetic landscape generated by random chalcogen substitution. Microscopic simulations reproduce the experimental trends and show that the character of disorder depends critically on the direction of alloying, producing either scattering barriers or deep trapping sites. Together, these results demonstrate that transport in TMD alloys is governed by disorder physics, overlooked by conventional optical and photoemission probes at equilibrium. Our findings establish transport as a stringent metric of electronic quality and high-light intrinsic limitations in the usage of TMD alloys for layered semiconductor devices.
ER  -