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Measurement of the atomic orbital composition of the near-fermi-level electronic states in the lanthanum monopnictides LaBi, LaSb, and LaAs

DOI: 10.1038/s41535-018-0094-3 DOI Help

Authors: Thomas J. Nummy (University of Colorado) , Justin A. Waugh (University of Colorado) , Stephen P. Parham (University of Colorado) , Qihang Liu (University of Colorado) , Hung-Yu Yang (Boston College) , Haoxiang Li (University of Colorado) , Xiaoqing Zhou (University of Colorado) , Nicholas C. Plumb (Swiss Light Source) , Fazel F. Tafti (Boston College) , Daniel S. Dessau (University of Colorado)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Npj Quantum Materials , VOL 3

State: Published (Approved)
Published: May 2018

Open Access Open Access

Abstract: Recent debates in the literature over the relationship between topology and Extreme Magnetoresistance (XMR) have drawn attention to the Lanthanum Monopnictide family of binary compounds. Angle resolved photoemission spectroscopy (ARPES) is used to measure the electronic structure of the XMR topological semimetal candidates LaBi, LaSb, and LaAs. The orbital content of the near-E F states in LaBi and LaSb are extracted using varying photon polarizations and both dominant d and p bands are observed near X. The measured bulk bands are shifted in energy when compared to the results of Density Functional Calculations. This disagreement is minor in LaBi, but large in LaSb and LaAs. The measured bulk band structure of LaBi shows a clear band inversion and puts LaBi in the υ = 1 class of Topological Insulators (or semimetals), as predicted by calculations and consistent with the measured Dirac-like surface states. LaSb is on the verge of a band inversion with a less-clear case for any distinctly topological surface states and in disagreement with calculations. Lastly, these same bands in LaAs are clearly non-inverted implying its topological triviality and demonstrating a topological phase transition in the Lanthanum monopnictides. Using a wide range of photon energies the true bulk states are cleanly disentangled from the various types of surface states which are present. These surface states exist due to surface projections of bulk states in LaSb and for topological reasons in LaBi.

Subject Areas: Physics, Materials

Instruments: I05-ARPES

Other Facilities: Swiss Light Source

Added On: 14/06/2018 11:48


Discipline Tags:

Hard condensed matter - electronic properties Physics Hard condensed matter - structures Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)