论文标题
Ti-Si无定形合金中特定热的临界行为
Critical behavior of the specific heat in Ti-Si amorphous alloys at the metal-insulator transition
论文作者
论文摘要
在本文中，我们报告了无定形$ ti_ {9.5} si_ {90.5} $合金的特定热量的测量值。在存在磁场的情况下，特异性热由与无定形SI基质中的悬挂键相关的磁矩引起的shottky异常主导。这种贡献的减法暴露了电子特定热系数$γ$的行为。该系数在2 K以上是与温度无关的，并且按照数量级的顺序接近在没有电子电子相互作用的情况下预期的值。在温度范围为0.4-1.5 K的温度范围内，系数$γ$显示出异常的低迷，可以通过依赖性$γ\ left（t \ right）=γ_0LN{（T/T_0）} $近似，$ t_0 \ t_0 \ of。在同伴纸中，我们发现TI-SI合金中的霍尔系数受电子相互作用的影响，直至更高的温度为150 K，并且在整个金属绝缘体过渡过程中也有很大的变化。我们将结果与三个模型的理论预测进行了比较，这可以解释特定热量的异常行为：广义的非线性$σ$模型，库仑玻璃和多体定位。
In this paper, we report the measurements of specific heat of an amorphous $Ti_{9.5}Si_{90.5}$ alloy located very close to the critical point of the metal-insulator transition. In the presence of a magnetic field, the specific heat is dominated by the Schottky anomaly caused by magnetic moments associated with the dangling bonds in the matrix of amorphous Si. Subtraction of this contribution exposes the behavior of the electronic specific heat coefficient $γ$. The coefficient is temperature-independent above 2 K and is, in order of magnitude, close to the value expected in the absence of electron-electron interactions. In the temperature range 0.4-1.5 K, the coefficient $γ$ shows an anomalous downturn, which can be approximated by the dependence $γ\left(T\right)=γ_0ln{(T/T_0)}$, with $T_0\approx0.2$ K . In a companion paper, we found that the Hall coefficient in Ti-Si alloys is affected by the electron-electron interaction up to much higher temperature of 150 K and also varies critically across the metal-insulator transition. We compare our results with theoretical predictions for three models, which can potentially explain the anomalous behavior of the specific heat: generalized non-linear $σ$ model, Coulomb glass, and many-body localization.
