High-pressure crystal structure and unusual magnetoresistance of a single-component molecular conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate)

DOI: 10.3390/cryst11050534

Authors: Hengbo Cui (Condensed Molecular Materials Laboratory RIKEN) , Hamish H.-M. Yeung (University of Birmingham; Oxford University) , Yoshitaka Kawasugi (Condensed Molecular Materials Laboratory RIKEN) , Takaaki Minamidate (Condensed Molecular Materials Laboratory RIKEN) , Lucy K. Saunders (Diamond Light Source) , Reizo Kato (Condensed Molecular Materials Laboratory RIKEN)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Crystals , VOL 11

State: Published (Approved)
Published: May 2021
Diamond Proposal Number(s): 20934

Abstract: A single-component molecular crystal [Pd(dddt)2] has been shown to exhibit almost temperature-independent resistivity under high pressure, leading theoretical studies to propose it as a three-dimensional (3D) Dirac electron system. To obtain more experimental information about the high-pressure electronic states, detailed resistivity measurements were performed, which show temperature-independent behavior at 13 GPa and then an upturn in the low temperature region at higher pressures. High-pressure single-crystal structure analysis was also performed for the first time, revealing the presence of pressure-induced structural disorder, which is possibly related to the changes in resistivity in the higher-pressure region. Calculations based on the disordered structure reveal that the Dirac cone state and semiconducting state coexist, indicating that the electronic state at high pressure is not a simple Dirac electron system as previously believed. Finally, the first measurements of magnetoresistance on [Pd(dddt)2] under high pressure are reported, revealing unusual behavior that seems to originate from the Dirac electron state.

Journal Keywords: single-component molecular conductor; pressure effect; Dirac electron system; resistivity; magnetoresistance; synchrotron X-ray diffraction; band calculation

Diamond Keywords: Semiconductors

Subject Areas: Materials, Chemistry


Instruments: I19-Small Molecule Single Crystal Diffraction

Added On: 22/05/2021 11:36

Discipline Tags:

Quantum Materials Physical Chemistry Chemistry Materials Science Inorganic Chemistry

Technical Tags:

Diffraction High Pressure Single Crystal Diffraction