Potential Lifshitz transition at optimal substitution in nematic pnictide Ba1−xSrxNi2As2

DOI: 10.1126/sciadv.adi4966

Authors: Dushyant Narayan (University of Colorado Boulder) , Peipei Hao (University of Colorado Boulder) , Rafal Kurleto (University of Colorado Boulder) , Bryan S. Berggren (University of Colorado Boulder) , A. Garrison Linn (University of Colorado Boulder) , Christopher Eckberg (University of Maryland) , Prathum Saraf (University of Maryland) , John Collini (University of Maryland) , Peter Zavalij (University of Maryland) , Makoto Hashimoto (Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory) , Donghui Lu (Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory) , Rafael M. Fernandes (University of Minnesota) , Johnpierre Paglione (University of Maryland; Canadian Institute for Advanced Research) , Daniel S. Dessau (University of Colorado Boulder)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Science Advances , VOL 9

State: Published (Approved)
Published: October 2023
Diamond Proposal Number(s): 25827

Abstract: BaNi2As2 is a structural analog of the pnictide superconductor BaFe2As2, which, like the iron-based superconductors, hosts a variety of ordered phases including charge density waves (CDWs), electronic nematicity, and superconductivity. Upon isovalent Sr substitution on the Ba site, the charge and nematic orders are suppressed, followed by a sixfold enhancement of the superconducting transition temperature (Tc). To understand the mechanisms responsible for enhancement of Tc, we present high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements of the Ba1−xSrxNi2As2 series, which agree well with our density functional theory (DFT) calculations throughout the substitution range. Analysis of our ARPES-validated DFT results indicates a Lifshitz transition and reasonably nested electron and hole Fermi pockets near optimal substitution where Tc is maximum. These nested pockets host Ni dxz/dyz orbital compositions, which we associate with the enhancement of nematic fluctuations, revealing unexpected connections to the iron-pnictide superconductors. This gives credence to a scenario in which nematic fluctuations drive an enhanced Tc.

Subject Areas: Materials, Physics


Instruments: I05-ARPES

Other Facilities: 5-2 at SSRL; 7 (Microscopic and Electronic STRucture Observatory, MAESTRO) at ALS

Added On: 23/10/2023 08:30

Documents:
sciadv.adi4966.pdf

Discipline Tags:

Superconductors Quantum Materials Physics Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)