Strong correlations between conduction electrons and magnetic moments reflect the competition between moment instabilities and magnetic order. Investigations of the resulting collective phases and complex phase diagrams in 3D compounds continue to reveal new behaviors, although similar efforts on 1D systems remain very limited due to a lack of suitable materials. We present here experimental evidence for 1D excitations in Ti4MnBi2, a moderately correlated metal consisting of well-separated chains of spin S = 1/2 moments. Inelastic neutron scattering (INS) measurements complemented by DMRG calculations show that Ti4MnBi2 is well described by the frustrated J1- J2 XXZ Hamiltonian, displaying a continuum of spinon excitations based on an underlying AF ↑↑↓↓ modulation of the Ising-like Mn moments along the chain. This is evidence for the one- dimensionality of the Mn subsystem. Fermi liquid behavior is observed in both the specific heat and electrical resistivity at low temperatures, indicating that the conduction electrons are three-dimensional, with magnetic correlations similar in strength to those found in metallic cuprates and ruthenates.
Using a combination of inelastic neutron scattering measurements and DMRG calculations, we explore the phase diagram of Ti4MnBi2 as a function of magnetic fields transverse to the chain direction. Highlights include the collapse of the underlying antiferromagnetic phase at a quantum critical point (QCP), and the emergence of magnon pair excitations at the highest fields. We discuss the possible role of Kondo coupling of the Mn moments to the conduction electrons in determining the lifetimes of the spinons and magnons, and in restructuring their excitations near the AF QCP.
This work is a collaboration with Xiyang Li, Igor Zaliznyak, Alberto Nocera, Kateryna Foyetsova, and George Sawatzky. This research was supported by the US National Science Foundation through grant NSF-DMR-1807451, by the Natural Sciences and Engineering Research Council of Canada (NSERC), and by the Stewart Blusson Quantum Matter Institute by the Canada First Research Excellence Fund (CFREF).
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2025-11-27T10:00:002025-11-27T11:00:00Towards One Dimensional Heavy FermionsEvent Information:
Strong correlations between conduction electrons and magnetic moments reflect the competition between moment instabilities and magnetic order. Investigations of the resulting collective phases and complex phase diagrams in 3D compounds continue to reveal new behaviors, although similar efforts on 1D systems remain very limited due to a lack of suitable materials. We present here experimental evidence for 1D excitations in Ti4MnBi2, a moderately correlated metal consisting of well-separated chains of spin S = 1/2 moments. Inelastic neutron scattering (INS) measurements complemented by DMRG calculations show that Ti4MnBi2 is well described by the frustrated J1- J2 XXZ Hamiltonian, displaying a continuum of spinon excitations based on an underlying AF ↑↑↓↓ modulation of the Ising-like Mn moments along the chain. This is evidence for the one- dimensionality of the Mn subsystem. Fermi liquid behavior is observed in both the specific heat and electrical resistivity at low temperatures, indicating that the conduction electrons are three-dimensional, with magnetic correlations similar in strength to those found in metallic cuprates and ruthenates.
Using a combination of inelastic neutron scattering measurements and DMRG calculations, we explore the phase diagram of Ti4MnBi2 as a function of magnetic fields transverse to the chain direction. Highlights include the collapse of the underlying antiferromagnetic phase at a quantum critical point (QCP), and the emergence of magnon pair excitations at the highest fields. We discuss the possible role of Kondo coupling of the Mn moments to the conduction electrons in determining the lifetimes of the spinons and magnons, and in restructuring their excitations near the AF QCP.
This work is a collaboration with Xiyang Li, Igor Zaliznyak, Alberto Nocera, Kateryna Foyetsova, and George Sawatzky. This research was supported by the US National Science Foundation through grant NSF-DMR-1807451, by the Natural Sciences and Engineering Research Council of Canada (NSERC), and by the Stewart Blusson Quantum Matter Institute by the Canada First Research Excellence Fund (CFREF).Event Location:
BRIM 311