Electronic Topological Transition in Ag2Te at High-pressure
Yuhang Zhang1, Yan Li1, Yanmei Ma1
1State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
Scientific Reports
|October 1, 2015
Summary
Silver telluride (Ag2Te) exhibits a pressure-induced electronic topological transition (ETT) at 1.8 GPa. This transition reveals unique insulating properties and structural phase changes, leading to metallization under high pressure.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Chemistry
Background:
- Silver telluride (Ag2Te) is a known 3D topological insulator (TI) at ambient conditions.
- High-pressure properties and behaviors of Ag2Te remain largely unexplored.
Purpose of the Study:
- To investigate the high-pressure electronic and structural properties of Ag2Te.
- To identify pressure-induced phase transitions and electronic topological transitions (ETT).
Main Methods:
- First-principle calculations and in situ high-pressure resistivity measurements.
- In situ high-pressure synchrotron powder X-ray diffraction (XRD).
- CALYPSO methodology for structural determination.
Main Results:
- A novel pressure-induced electronic topological transition (ETT) in Ag2Te at 1.8 GPa.
- Ag2Te exhibits a positive pressure coefficient of bulk band-gap, a first for TIs.
- Electrical resistivity peaks at 1.8 GPa, indicating optimal insulating and topological properties.
- Determined the phase transition sequence: P21/c → Cmca → Pnma, correcting previous structural assignments.
- Confirmed pressure-induced metallization at elevated pressures.
Conclusions:
- Ag2Te undergoes significant electronic and structural transformations under pressure.
- The material shows tunable electronic properties, transitioning from insulator to metal.
- The findings provide a comprehensive understanding of Ag2Te's high-pressure phase diagram and topological nature.
Related Concept Videos
02:58Properties of Transition Metals
30.8K
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
30.8K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
3.5K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
3.5K
02:33Phase Transitions: Sublimation and Deposition
20.9K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.9K