Single-component molecular conductor [Pt(dmdt)₂]—a three-dimensional ambient-pressure molecular Dirac electron system

Abstract

[Pt(dmdt)2], an air-stable single-component molecular conductor, contains massless Dirac electrons and carries Dirac nodal lines at ambient pressure.

Tight-Binding Model and Electronic Property of Dirac Nodal Line in Single-Component Molecular Conductor [Pt(dmdt)2]

“…In addition, we calculate the magnetic susceptibility. We show that the T -linear behavior of the magnetic susceptibility at a high temperature is consistent with the experimental result, 28) supporting the existence of Dirac nodal line. We argue that the depletion of the magnetic susceptibility observed experimentally at a low temperature 28) cannot be explained only by the effect of a realistic SOC.…”

“…A characteristic of the energy band structure of [Pt(dmdt) 2 ] is the three isolated bands near the Fermi energy. 28) We construct the three-orbital tight-binding model focusing on these three isolated bands by Wannier fitting. Fig.…”

“…Recently, in addition to graphite, various Dirac nodal line semimetals have been found; such semimetals are transition-metal monophosphates, 15) Cu 3 N, 16) antiperovskites, 17) perovskite iridates, 18) the hexagonal pnictides CaAgX (X = P, As), 19) and the single-component molecular conductors [Pd(dddt) 2 ] [20][21][22][23][24][25][26][27] and [Pt(dmdt) 2 ]. 28) The Dirac electron systems exhibit anomalous behaviors in large orbital diamagnetism, 29,30) electrical resistivity, 31) Hall coefficient, [32][33][34] and topological edge states. 35) In the Dirac nodal line semimetals, a flat Landau level, 36) the Kondo effect, 37) long-range Coulomb interaction, 38) and a quasi-topological electromagnetic response 39) are also expected.…”

High Pressure Crystal Structure and Electrical Properties of a Single Component Molecular Crystal [Ni(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate)

“…Previous studies of its analogs, [Au(Et-thiazdt) 2 ] [7] and [Au(Et-thiazds) 2 ], which features S substituted by Se [8], showed that they turn metallic at 1.3 GPa and 0.6 GPa, respectively, values which compare favorably with the simple metal dithiolene complex, [Ni(dmit) 2 ], which becomes metallic at 15.9 GPa [9]. In single-component molecular conductors that meet certain conditions, the HOMO band and LUMO band can touch at a single point to form a Dirac electron system [10,11]. We have employed first-principles density functional theory (DFT) calculations to understand the single-component crystal [Pd(dddt) 2 ] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate), which exhibits temperature-independent resistivity at 12.6 GPa.…”

Novel Dirac Electron in Single-Component Molecular Conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate)

“…[10][11][12][13][14][15] Indeed, after this discovery, the semimetal with open nodal lines has been found in another single-component molecular conductor [Pt(dmdt) 2 ] (dmdt = dimethyltetrathiafulvalenedithiolate). [16][17][18] Nodal-line semimetals where the conduction and valence bands touch each other along a line in the three-dimensional Brillouin zone have aroused broad interest in the possibility of topologically nontrivial states. [19][20][21][22][23][24][25][26][27][28] The crystal of metal dithiolene complex [Pd(dddt) 2 ] is an insulator at ambient pressure.…”