Potential Lifshitz transition at optimal substitution in nematic pnictide Ba1xSrxNi2As2
- University of Colorado, Boulder, CO (United States)
- University of Maryland, College Park, MD (United States)
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
- University of Minnesota, Minneapolis, MN (United States)
- University of Maryland, College Park, MD (United States); Canadian Institute for Advanced Research, Toronto (Canada)
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.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Gordon and Betty Moore Foundation; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
- Grant/Contract Number:
- AC02-76SF00515; FG02-03ER46066; GBMF9458; AC02-05CH11231; DMR1905891; GBMF9071; SC0020045; ACI-1532235; ACI-1532236
- OSTI ID:
- 2281585
- Journal Information:
- Science Advances, Vol. 9, Issue 42; ISSN 2375-2548
- Publisher:
- AAASCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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