Electronic properties of layered rhenium dichalcogenides

Student thesis: Doctoral ThesisPhD


We study the semiconducting rhenium dichalcogenides ReX2, where X is sulfur (S)

or selenium (Se), a class of transition metal dichalcogenides (TMDs) with a distorted

lattice structure. These materials have a single symmetry operation: inversion symmetry,

which leads to a lack of spin-orbit splitting. We use density functional theory (DFT) to

study the electronic dispersion of bulk ReSe2 and ReS2, which have complicated band

structures with many close-lying band gaps. We show the importance of studying the full

Brillouin zone rather than only the high symmetry points when trying to determine the

nature of the band gap in these materials. Thereafter, we calculate the band structure of

monolayer ReSe2 and identify which orbitals contribute to the low energy behaviour at

the valence band edge. We compare our DFT calculations to experimental angle-resolved

photoemission spectroscopy (ARPES) measurements. Furthermore, we compare DFT

data to ARPES data which uses different polarisations, exploiting the symmetry of

the underlying atomic orbitals. We find that the out-of-plane orbitals do not contribute

significantly to the top of the valence band, unlike in many other TMDs. These materials

are thus shown to display quasi-one-dimensional behaviour, with anisotropy along the

Re chains. We then calculate band structures of Janus ReSSe, where the chalcogen layers

on either side of Re are composed of S on one side and Se on the other. The distorted

structures of rhenium TMDs motivates the study of Janus-like rhenium dichalcogenides

with varying numbers of substituted chalcogens in pure ReSe2 or ReS2. We calculate

formation energies and predict the substitutions most likely to take place, before showing

the effect of these substitutions on the valence and conduction bands. The broken

inversion symmetry in these Janus and Janus-like materials leads to significant spinorbit

splitting, which could have uses in spintronics applications. Hence, we have studied

the band structures of rhenium dichalcogenides and shown that these materials have

complicated band structures and strong anisotropy which lead to interesting effects not

seen in other TMDs, making them promising candidates for applications in optoelectronic


Date of Award16 Jun 2021
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorMarcin Mucha-Kruczynski (Supervisor) & Daniel Wolverson (Supervisor)


  • TMD
  • DFT
  • Rhenium

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