Argonne National Laboratory

Research Highlight | Center for Nanoscale Materials

Molecular charge density waves in a single layer fermion system
In a study published in ACS Nano, researchers discovered two-dimensional charge density waves on a silver surface.
STM image of CDW in (BEDT-TTF)₂-I₃ molecular layer (left). CDW is also observed on the surface of single-layer thick molecular islands (right).

Scientific Achievement

Robust two-dimensional charge density waves (CDW) are discovered in organic-inorganic molecular islands of just a single constituent thickness on a Ag(111) surface.  

Significance and Impact

CDW is intensely studied in inorganic materials such as high Tc superconductors; the discovery of CDW in just a single-layer thick molecular island opens a new avenue of research in strongly correlated systems formed by organic molecules. 

Research Details

  • α-(BEDT-TTF)2-I3 films were studied via scanning tunneling microscopy (STM) at the Center for Nanoscale Materials 9CNM) and Ohio University.
  • STM images at 80 K and 5 K reveal coexistence of certain CDW patterns commensurate with the underlying molecular lattice.
  • The CDW can be shifted a molecular lattice site by energy transfer of a single inelastic tunneling electron.
  • DFT calculations were performed at the CNM.

Work was performed in part at the CNM.

DOI: 10.1021/acsnano.0c03694

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About Argonne’s Center for Nanoscale Materials
The Center for Nanoscale Materials is one of the five DOE Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit https://​sci​ence​.osti​.gov/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​-​a​t​-​a​-​G​lance.

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