DQMP Forum - Bulk and Surface Electronic Structure of the Dual-topology Semimetal Pt2HgSe3 - Presentation of our New Rigaku XtaLAB Synergy-S Diffractometer

10.04.2020 13:00 – 14:30

Bulk and Surface Electronic Structure of the Dual-topology Semimetal Pt2HgSe3
Irène Cucchi (Group of Prof. Baumberger)

We present the electronic structure of bulk (001)-Pt2HgSe3 measured by angle-resolved photoelectron spectroscopy (ARPES). In monolayer form, this material is predicted to be a 2D quantum spin hall insulator (QSHI) with an 0.5 eV gap. In bulk form, theoretical predictions suggest a dual topology: Pt2HgSe3 would host a topological crystalline phase in addition to the weak topological phase naturally arising from the 3D stacking of 2D topological insulators. This prediction was not experimentally
verified until we performed ARPES measurements on Pt2HgSe3 single crystals. Our measurements reveal a surface state emerging from a nodal line gapped by spin-orbit interactions. Comparing ARPES data with density functional theory (DFT) calculations, we identify this surface state as signature of a topological crystalline insulator phase. The good agreement between DFT calculations and ARPES measurements provides evidence for the dual topological nature of bulk Pt2HgSe3 and supports the prediction of a QSHI phase in monolayer Pt2HgSe3.


Presentation of our New Rigaku XtaLAB Synergy-S Diffractometer
Céline Besnard (Group of Prof. Cerny)

The new single-crystal X-ray diffractometer recently installed in the Laboratory of Crystallography will be shortly presented. This dual micro-focus source diffractometer (Mo, Cu) is equipped with a new generation curved photon counting X-ray detector (RIGAKU Hypix arc 150), allowing very fast measurements since more data are collected in a single exposure. The detector has almost zero noise, fast readout and energy discrimination. The goniometer is a 4-circle kappa goniometer. The diffractometer is equipped with a cooling system allowing measurements within a temperature range of 80-500K (Oxford Cryosystem Cryostream 800 plus).

Forum Committee: C. Lichtensteiger, N. Ubrig, A. Tamai (March 2, 2020)

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre