Anisotropic Hc2, shubnikov de haas, and angular dependent magnetoresistance in the organic superconductor a-(BEDT-TTF)2MHg(SCN)4

The electrodynamic response of single crystals of the quasi-two-dimensional organic metal between 50 and 100 GHz: observation of cyclotron resonance and quantum oscillations

“…Quantum oscillations can clearly be seen in the absorption when B 11 T. The frequency of the oscillations is about 570 ± 10 T, in good agreement with the Shubnikov-de Haas oscillation frequency observed in conventional (DC or low-frequency AC) magnetotransport and magnetization experiments [3,10,12,15,16]. The limited temperature range of the apparatus (T 1.5 K) leads to the effective mass derived from the temperature dependence of the quantum oscillations in this work being insufficiently accurate for meaningful comparisons with the other studies; however, over the limited range studied, the temperature dependence of the amplitude of the quantum oscillations appears similar to those observed in conventional experiments [3,15,16].…”

“…Its calculated Fermi surface consists of a quasi-two-dimensional (Q2D) warped cylinder (holes), with a cross-sectional area corresponding to a quantum oscillation (de Haas-van Alphen or Shubnikov-de Haas) frequency of about 570 T, and two quasi-one-dimensional Fermi sheets (electrons), slightly warped in both the in-plane and interplane directions [9]. The cylinder is thought to be corrugated by 1% [10,11]. The in-plane resistivity of this material is typically 10 m cm at 4.2 K [12], with an inplane anisotropy of around 3-5; the interplane resistivity is approximately 5-6 orders of magnitude larger [9,12].…”

Bulk two-dimensional Pauli-limited superconductor

“…The anisotropy parameter (γ) for ET-NH4 = 2000, while γ=150 for Bi 2 Sr 2 CaCu 2 O 8+δ [27]. The high anisotropy in ET-NH4 produces a broad, zero-field resistive transition (reported onset temperatures vary from 1.2 K to 2.4 K [27][28][29][30][31][32]), a broad peak in the zero-field specific heat at T c [25][26][27], anisotropic penetration depths (λ ⊥ = 1400 µm and λ = 0.7 µm as T → 0 [27], and anisotropic resistivity (20 Ω • cm ≤ ρ ⊥ ≤ 40 Ω • cm and 10 µΩ • cm ≤ ρ ≤ 100 µΩ • cm at 3 K [27]).…”