Bond competition and phase evolution on the IrTe2 surface
Qing Li1,2, Wenzhi Lin1, Jiaqiang Yan3,4, Xin Chen4, Anthony G. Gianfrancesco5, David J. Singh4,David Mandrus3,4, Sergei V. Kalinin1 & Minghu Pan1,6
1 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
2 Institute of Functional Nano and Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Science and Technology, Soochow University, Jiangsu 215123, China.
3 Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.
4 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056, USA.
5 UT/ORNL Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996, USA.
6 School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China. Correspondence and requests for materials should be addressed to S.V.K. (email: sergei2@ornl.gov) or to M.P. (email: mhupan@gmail.com).
Compounds with incommensurate structural modulations have been extensively studied in last several decades. However, the relationship between structurally incommensurate/commensurate phases and associated electronic states remains enigmatic. Here we report the coexisting of complex incommensurate structures and highly unusual electronic roughness on the surface of in situ cleaved IrTe2 by using scanning tunnelling microscopy/spectroscopy, corroborated with extensive density-functional theory calculations. This behaviour is traced to structural instability, which induces a structural transition from a trigonal to a triclinic lattice below transition temperature, giving rise to the formation of unidirectional structural modulations with distinct wavelengths, accompanied by the opening of a ‘pseudo’-gap in the surface layer. With further cooling the surface adopts a structure that reflects an B ~6 X periodicity that is different from the bulk 5 X periodicity. Calculations show that the structure distortion is not associated with a charge density wave, but is rather associated with Te p-electron bonding.
NATURE COMMUNICATIONS | 5:5358 | DOI: 10.1038/ncomms6358 | www.nature.com/naturecommunications
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