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SYME: Symposium Frontiers of Electronic Structure Theory: Many-body Effects on the Nano-Scale
SYME 6: Frontiers of Electronic Structure Theory: Many-Body Effects on the Nano-Scale V
SYME 6.2: Vortrag
Donnerstag, 19. März 2015, 11:00–11:15, MA 004
Screening of the Coulomb interaction in two-dimensional semiconductors: The case of transition metal dichalcogenides — •Ersoy Sasioglu, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute forAdvanced Simulation, Forschungszentrum Jülich and JARA, 52425Jülich, Germany
Experimentally determined large exciton binding energies and nonhydrogenic Rydberg series in monolayer transition metal (TM) dichalcogenides indicate a long-range behavior of the Coulomb interaction. By means of first-principles calculations in conjunction with the random-phase approximation [1,2] within the FLAPW method [3] we study screening of the Coulomb interaction in two-dimensional semiconducting TM dichalcogenides MX2 (M=Cr, Mo, W; X=S, Se). We show that the screening in these systems deviates
substantially from the bulk behavior, i.e., the short-range interaction is strongly screened, while the long-range interaction is anti-screened. This unconventional screening
reduces the gradient of the Coulomb interaction giving rise to weak correlation effects, which explains the experimentally observed large exciton binding energies as well as the success of the one-particle density functional theory in the description of the electronic structure of
these systems. This work has been supported in part by DFG-FOR-1346.
C. Friedrich et al., Phys. Rev. B. 81, 125102 (2010).
E. Şaşioğlu et al., Phys. Rev. B 83, 121101(R) (2011).
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