Thermodynamic evidence for valley-dependent density of states in bulk bismuth
Thermodynamic evidence for valley-dependent density of states in bulk bismuth
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DOI：
10.1038/nmat3909
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发表时间：
2014-05-01
期刊：
影响因子：
41.2
通讯作者：
Steglich, F.
中科院分区：
文献类型：
--
作者：
Kuechler, R.;Steinke, L.;Steglich, F.
铋中的类电子载流子由狄拉克哈密顿量描述，其能带质量沿沿着一个晶轴变为裸电子质量的千分之一（1）。三个各向异性谷的存在为电子提供了额外的自由度，这是最近关注的主题（2）。在这里，我们通过角分辨磁致伸缩绘制了朗道谱，并量化了每个谷中的载流子数：虽然电子谷保持相同的谱，但它们在费米能级上的态密度却有很大的不同。因此，即使在没有内部应变的情况下，电子流体在低温和高磁场下也不保持晶格的旋转对称性。这种效应，让人联想到局域电子态中的库仑赝能隙，只影响费米能级附近的电子。它提出了最显着的偏离非相互作用的电子在散装铋图片。
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(1). The existence of three anisotropic valleys offers electrons an additional degree of freedom, a subject of recent attention(2). 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.