1] Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany [2].
1] Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany [2] Crismat, UMR 6508, F-14050 Caen, France.
Nat Mater. 2014 May;13(5):461-5. doi: 10.1038/nmat3909. Epub 2014 Mar 16.
Electron-like carriers in bismuth are described by the Dirac Hamiltonian, with a band mass becoming a thousandth of the bare electron mass along one crystalline axis. The existence of three anisotropic valleys offers electrons an additional degree of freedom, a subject of recent attention. Here, we map the Landau spectrum by angle-resolved magnetostriction, and quantify the carrier number in each valley: while the electron valleys keep identical spectra, they substantially differ in their density of states at the Fermi level. Thus, the electron fluid does not keep the rotational symmetry of the lattice at low temperature and high magnetic field, even in the absence of internal strain. This effect, reminiscent of the Coulomb pseudogap in localized electronic states, affects only electrons in the immediate vicinity of the Fermi level. It presents the most striking departure from the non-interacting picture of electrons in bulk bismuth.
在铋中，类电子载流子由狄拉克哈密顿量描述，其中沿一个晶轴的能带质量变为裸电子质量的千分之一。三个各向异性谷为电子提供了额外的自由度，这是最近关注的一个主题。在这里，我们通过角分辨磁致伸缩来绘制朗道能谱，并量化每个谷中的载流子数量：虽然电子谷保持相同的谱，但它们在费米能级处的态密度有很大差异。因此，即使在没有内应变的情况下，电子流体在低温和强磁场下也不会保持晶格的旋转对称性。这种效应类似于局域电子态中的库仑赝能隙，仅影响费米能级附近的电子。这是从块状铋中电子的非相互作用图像最显著的偏离。
