Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Two-dimensional Materials I (joint session HL/CPP)
HL 17.4: Vortrag
Dienstag, 2. April 2019, 10:15–10:30, H36
Many-body quantum Monte Carlo study of 2D materials: cohesion and band gap in single-layer phosphorene — •Tobias Frank1, Rene Derian2, Kamil Tokar2, Lubos Mitas3, Jaroslav Fabian1, and Ivan Stich2,4 — 1University of Regensburg, Regensburg, Germany — 2Slovak Academy of Sciences, Bratislava, Slovakia — 3North Carolina State University, Raleigh, NC — 4University of Ss. Cyril and Methodius, Trnava, Slovakia
Quantum Monte Carlo (QMC) is applied to obtain the fundamental (quasiparticle) electronic band gap, Δf, of a semiconducting 2D phosphorene. Similarly to other 2D materials, the electronic structure of phosphorene is strongly influenced by reduced screening, making it challenging to obtain reliable predictions by conventional methods. Using the recently uncovered universal scaling between the exciton binding energy and Δf, we predict the optical gap of about 1.7 eV that can be directly related to experiments. The QMC gaps agree with recent optical absorption and photoluminescence measurements. We also predict the cohesion of phosphorene to be only slightly smaller than that of the bulk crystal. Our investigations not only benchmark GW methods and experiments, but also open the field of 2D electronic structure to computationally intensive but highly predictive QMC methods which include many-body effects such as electronic correlations. We were supported by GRK Grant No. 1570, the International Doctorate Program Topological Insulators of the Elite Network of Bavaria, and DFG SFB 1277 (B07). We acknowledge the Gauss Centre for Supercomputing (www.gauss-centre.eu) for funding.