Pressure Effect on Fermi Surface in β″-(ET)(TCNQ)

• Published in: Synthetic metals Vol. 152; no. 1; pp. 437 - 440
• Main Authors: Yasuzuka, S., Uji, S., Enomoto, K., Konoike, T., Nishimura, M., Terashima, T., Graf, D., Choi, E.S., Brooks, J.S., Yamamoto, H.M., Kato, R., Yokogawa, K., Murata, Keizo
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 20.09.2005; Amsterdam Elsevier Science; New York, NY
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; Fermi surface: calculations and measurements; effective mass, g factor; Metal-insulator phase transition; Organic conductors based on radical cation and/or anion salts; Physics; Transport measurements; Organic conductors based on radical cation and/or anion salts; Metal-insulator phase transition; Transport measurements; Metallic conduction; Pressure effects; Organic conductors; Metal-insulator transition; TCNQ; BEDT-TTF; Angular variation; Anomaly; Fermi surface; transport measurements; Magnetoresistance
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2005.07.165

In order to investigate the electronic state, we have performed the resistance measurements of β″-(ET)(TCNQ) under pressures. At ambient pressure, the resistance shows metallic behavior down to 0.5 K with three hump anomalies at T 1(=20 K), T 2(=60 K), and T 3(=250 K). As the sample is pressurized, the anomalies at T 1 and T 3 are strongly suppressed, and only the anomaly at T 2 is observed at 5.1 kbar. The angular-dependent magnetoresistance shows resonance structures under fields in both b*- c and b*- a planes, which arises from one-dimensional Fermi surfaces of the ET and TCNQ bands, respectively. The results are consistent with the band calculation, and also suggest that the Fermi surface is not reconstructed at T 2. The origin of the anomaly at T 2 is still an open question.