Thermodynamic study of multilayer Dirac electron system

我们测量了有机导体α-（BEDT-TTF）_2I_3在压力下的比热，实现了具有线性能量色散的无质量狄拉克费米子系统。在低温下，比热几乎与Δ T^2有关，在磁场中出现峰值和饱和。通过假设狄拉克费米子系统的线性色散和N=0的朗道能级特性，这些行为可以很好地理解。这一结果也与文献报道的磁电阻效应相当一致。

We have measured the specific heat of the organic conductor α-(BEDT-TTF)_2I_3 under pressure where the massless Dirac fermion system with linear energy dispersion is realized. In low temperature, the specific heat shows almost ∝T^2 dependence, and shows the peak and saturation in magnetic field. These behaviors are well understood by assuming the linear dispersion and N=0 Landau level characteristic of the Dirac fermion system. The results are also quite consistent with the reported magnetoresistance.