2019/11/30 by R. Rösslhuber, Roland Rösslhuber, Andrej Pustogow +16
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Chemistry #Condensed matter physics #Crystallography #Dielectric #Dimer #Hubbard model #Materials science #Mott insulator #Mott transition #Nuclear magnetic resonance #Order (exchange) #Organic and Molecular Conductors Research #Phase (matter) #Phase boundary #Physics #Quantum mechanics #Rare-earth and actinide compounds #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.103.125111
published as Phys. Rev. B 103, 125111 (2021)
openalex created_date 2019/12/05 · openalex publication_date 2021/03/05 · arxiv created 2021/03/10 · arxiv updated 2021/03/17 · openalex updated_date 2026/08/05
The dimer Mott insulator \ensuremathκ\text\ensuremath-(BEDT\text\ensuremath-TTF)2Cu2(CN)3 can be tuned into metallic and superconducting states on applying pressure of 1.5 kbar and more. We have performed dielectric measurements (7.5 kHz to 5 MHz) on \ensuremathκ\text\ensuremath-(BEDT\text\ensuremath-TTF)2Cu2(CN)3 single crystals as a function of temperature (down to T=8 K) and pressure (up to p=4.3 kbar). In addition to the relaxor-like dielectric behavior seen below 50 K at p=0, that moves toward lower temperatures with pressure, a second peak emerges in \ensuremathε1(T) around T=15 K. When approaching the insulator-metal boundary, this peak diverges rapidly reaching \ensuremathε1\ensuremath≈105. Our dynamical mean-field theory calculations substantiate that the dielectric catastrophe at the Mott transition is not caused by closing the energy gap, but due to the spatial coexistence of correlated metallic and insulating regions. We discuss the percolative nature of the first-order Mott insulator-to-metal transition in all details.