Spin-valley locking in the normal state of a transition-metal dichacogenide superconductor

Thiagarajan, BalasubramanianLund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory (author)

Metallic transition-metal dichalcogenides (TMDCs) are benchmark systems for studying and controlling intertwined electronic orders in solids, with superconductivity developing from a charge-density wave state. The interplay between such phases is thought to play a critical role in the unconventional superconductivity of cuprates, Fe-based and heavy-fermion systems, yet even for the more moderately-correlated TMDCs, their nature and origins have proved controversial. Here, we study a prototypical example, 2H-NbSe2, by spin- and angle-resolved photoemission and first-principles theory. We find that the normal state, from which its hallmark collective phases emerge, is characterized by quasiparticles whose spin is locked to their valley pseudospin. This results from a combination of strong spin–orbit interactions and local inversion symmetry breaking, while interlayer coupling further drives a rich three-dimensional momentum dependence of the underlying Fermi-surface spin texture. These findings necessitate a re-investigation of the nature of charge order and superconducting pairing in NbSe2 and related TMDCs.

Bawden, LUniversity of St Andrews (author)
Cooil, S. PNorwegian University of Science and Technology (author)
Mazzola, FNorwegian University of Science and Technology (author)
Collins-McIntyre, L. JUniversity of St Andrews (author)
Sunko, VUniversity of St Andrews,Max Planck Institute for Chemical Physics of Solids (author)
Hunvik, K. W. ENorwegian University of Science and Technology (author)
Leandersson, MatsLund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory(Swepub:lu)maxl-mle (author)
Polley, CraigLund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory(Swepub:lu)cr4837po (author)
Kim, T. MDiamond Light Source (author)
Hoesch, MDiamond Light Source (author)
Wells, J. W.Norwegian University of Science and Technology (author)
Balakrishnan, GUniversity of Warwick (author)
Bahramy, M. SRIKEN, Center for Emergent Matter Science,University of Tokyo (author)
King, P. D. CUniversity of St Andrews (author)
Riley, J. M.University of St Andrews,Diamond Light Source (author)
Lunds universitetMAX IV-laboratoriet (creator_code:org_t)

By the author/editor: Thiagarajan, Bal ...; Bawden, L; Cooil, S. P; Mazzola, F; Collins-McIntyre ...; Sunko, V; show more...; Hunvik, K. W. E; Leandersson, Mat ...; Polley, Craig; Kim, T. M; Hoesch, M; Wells, J. W.; Balakrishnan, G; Bahramy, M. S; King, P. D. C; Riley, J. M.; show less...

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Physical Science ...; and Condensed Matter ...

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