New research sheds light on the mechanism behind how a special material changes from an electrically conducting metal to an electric insulator. The researchers studied lanthanum strontium nickel oxide (La1.67Sr0.33NiO4) derived from a quantum material La2NiO4. Quantum materials have unusual properties that result from how their electrons interact. Below a critical temperature, the strontium doped material is an insulator. This is due to the separation of introduced holes from the magnetic regions, forming “stripes.” As the temperature increases, these stripes fluctuate and melt at 240K. At this temperature, researchers expected the material to become a conducting metal. Instead, it remains an insulating material. Neutron scattering sheds light on this intriguing phenomenon. The results indicate that the material stays an insulator because of certain atomic vibrations that trap electrons and thus impede electrical conduction.
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Source: Phys.org