Mapping the unoccupied state dispersions in Ta2NiSe5 with resonant inelastic x-ray scattering
- Universite de Fribourg (Switzerland)
- Universität Potsdam (Germany)
- Universite de Fribourg (Switzerland); LUT University, Lappeenranta (Finland)
- Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source; Chinese Academy of Sciences (CAS), Beijing (China)
- Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source; Brookhaven National Lab. (BNL), Upton, NY (United States)
- Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source; Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Diamond Light Source, Ltd.
- Nagoya Univ. (Japan)
- Okayama Univ. (Japan)
- Max Planck Institute for Solid State Research, Stuttgart (Germany); Univ. of Tokyo (Japan)
- Paul Scherrer Inst. (PSI), Villigen (Switzerland). Swiss Light Source
- Waseda Univ., Shinjuku (Japan)
The transition metal chalcogenide Ta2NiSe5 undergoes a second-order phase transition at Tc = 328 K involving a small lattice distortion. Below Tc, a band gap at the center of its Brillouin zone increases up to about 0.35 eV. In this work, we study the electronic structure of Ta2NiSe5 in its low-temperature semiconducting phase, using resonant inelastic x-ray scattering (RIXS) at the Ni L3-edge. In addition to a weak fluorescence response, we observe a collection of intense Raman-like peaks that we attribute to electron-hole excitations. Using density functional theory calculations of its electronic band structure, we identify the main Raman-like peaks as interband transitions between valence and conduction bands. Further, by performing angle-dependent RIXS measurements, we uncover the dispersion of these electron-hole excitations that allows us to extract the low-energy boundary of the electron-hole continuum. From the dispersion of the valence band measured by angle-resolved photoemission spectroscopy, we derive the effective mass of the lowest unoccupied conduction band.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Swiss National Science Foundation (SNSF); European Research Council (ERC)
- Grant/Contract Number:
- SC0012704; P00P2_170597; CRSII2_141962; CRSII2_160765; FP7/2007−2013; 290605
- OSTI ID:
- 1827150
- Report Number(s):
- BNL-222116-2021-JAAM; TRN: US2216036
- Journal Information:
- Physical Review B, Vol. 102, Issue 8; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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