Bond competition and phase evolution on the IrTe₂ surface.
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 ~6 × periodicity that is different from the bulk 5 × periodicity. Calculations show that the structure distortion is not associated with a charge density wave, but is rather associated with Te p-electron bonding.
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.
Qing
Q
Li
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Wenzhi
W
Lin
1] Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA [2] Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056, USA.
Jiaqiang
J
Yan
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056, USA.
Xin
X
Chen
UT/ORNL Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996, USA.
Anthony G
AG
Gianfrancesco
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056, USA.
David J
DJ
Singh
1] Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA [2] Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6056, USA.
David
D
Mandrus
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Sergei V
SV
Kalinin
1] Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA [2] School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
Minghu
M
Pan