Related Experiment Video
Updated: Apr 21, 2026
07:49
Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
10.6K
Bond competition and phase evolution on the IrTe₂ surface.
Qing Li1, Wenzhi Lin2, Jiaqiang Yan3
11] 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.
Nature Communications
|November 8, 2014
Summary
Researchers uncovered complex incommensurate structures and electronic roughness on IrTe₂ surfaces. This arises from a structural transition, creating a pseudo-gap and unique surface periodicity, linked to Te p-electron bonding.
Area of Science:
- Solid State Physics
- Materials Science
- Surface Science
Background:
- Incommensurate and commensurate structural phases are well-studied.
- The link between these phases and electronic states is not fully understood.
Purpose of the Study:
- Investigate the relationship between structural modulations and electronic states in IrTe₂.
- Understand the origin of unusual surface electronic properties.
Main Methods:
- In situ cleaved Iridium Ditelluride (IrTe₂) surface imaging and spectroscopy using scanning tunnelling microscopy/spectroscopy (STM/STS).
- Extensive density-functional theory (DFT) calculations.
Main Results:
- Observed coexisting complex incommensurate structures and electronic roughness on the IrTe₂ surface.
- Identified a structural transition from trigonal to triclinic lattice, forming unidirectional modulations and a surface pseudo-gap.
- Discovered a distinct surface periodicity (~6x) different from the bulk (5x) upon cooling.
- DFT calculations indicate the distortion is due to Te p-electron bonding, not a charge density wave.
Conclusions:
- Structural instability drives unique surface phenomena in IrTe₂.
- The observed electronic roughness and pseudo-gap are consequences of structural modulations.
- Te p-electron bonding plays a crucial role in the observed structural distortion and electronic properties.
Related Concept Videos
01:19Phase Diagram
7.3K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
7.3K
01:24Phase Diagram
165
A phase diagram is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. It shows the boundaries between solid, liquid, and gas phases and the conditions at which these phases coexist in equilibrium. An area in a phase diagram represents a single phase, whereas lines or phase boundaries represent the equilibrium between two phases.In the phase diagram of water, the boundary line between the solid and liquid states illustrates...
165
01:28Phase Diagrams of Ternary Systems
130
Consider a ternary system, which is composed of three components: water (W), ethanoic acid (E), and trichloromethane (T). Here, Ethanoic acid (E) is fully miscible with both water (W) and trichloromethane (T), meaning it can mix entirely with either of them. However, water and trichloromethane have partial miscibility, meaning they can only mix to a certain extent, beyond which two separate phases will form.The phase diagram of a ternary system is represented as an equilateral triangle, where...
130
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.7K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.7K
01:24π Molecular Orbitals of 1,3-Butadiene
13.0K
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the...
13.0K
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
5.3K
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
5.3K