Pressure-induced charge density wave phase in $\mathrm{A}{\mathrm{g}}_{2\text{-}\delta }\mathrm{Te}$

Journal Article · Thu Nov 15 00:00:00 EST 2018 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.98.205126· OSTI ID:1505175

Zhao, Yongsheng ^[1]; Yang, Wenge ^[1]; Schnyders, Harold S. ^[2]; Husmann, Anke ^[3]; Zhang, Ganghua ^[1]; Ren, Yang ^[4]; Price, David L. ^[5]; Mao, Ho-Kwang ^[6]; Saboungi, Marie-Louise ^[7]

---

1. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)
2. Grand Valley State Univ., Allendale, MI (United States). Physics Dept.
3. Univ. of Cambridge (United Kingdom). Dept. of Materials Science and Metallurgy
4. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS), X-Ray Science Division
5. Univ. d'Orléans, Orléans (France). CEMHTI
6. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China); Carnegie Inst. of Washington, Washington, DC (United States). Geophysical Lab.
7. National Centre for Scientific Research (CNRS), Paris (France); Sorbonne Univ., Paris (France). Inst. de minéralogie, de physique des matériaux et de cosmochimie (IMPMC)

Considerable excitement was generated by the observation of large and linear positive magnetoresistance in nonmagnetic silver chalcogenides. Renewed interest in these materials was kindled by the discovery that Ag₂Te in particular is a topological insulator with gapless linear Dirac-type surface states. High-pressure x-ray-diffraction studies, combined with first-principles electronic structure calculations, have identified three phase transitions as the pressure is increased: an isostructural transition identified with an electronic topological transition followed by two structural phase transitions. These recent studies were carried out on nominally stoichiometric Ag₂Te. For the present work we have prepared single-phase self-doped Ag_2-δTe samples with a well-characterized silver deficit (δ=2.0×10^-4) for structural and electrical transport measurements over extended ranges of pressure (0–43 GPa), temperature (2–300 K), and magnetic field (0–9 T). The temperature dependence of the resistivity exhibits anomalous behavior at 2.3 GPa, slightly above the isostructural transition, which we postulate is due to Fermi surface reconstruction associated with a charge density wave (CDW) phase. The anomaly is enhanced by the application of a 9-T magnetic field and shifted to higher temperature, implying that the electronic Zeeman energy is sufficient to alter the gapping of the Fermi surface. A peak in the pressure dependence of the resistivity and a sudden drop in the pressure dependence of the mobility, occurring at 2.3 GPa, provide additional evidence for a CDW phase at pressures slightly above the isostructural transition.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357; NA0001974; FG02-99ER45775
• OSTI ID: 1505175
• Alternate ID(s): OSTI ID: 1482283
• Journal Information: Physical Review B, Vol. 98, Issue 20; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE