No abstract

Purely quantum electron systems exhibit intriguing correlated electronic phases by virtue of quantum fluctuations in addition to electron-electron interactions. To realize such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid, which spreads up to ~ 3 Å in the vacuum on the surface of electride crystal. An extremely high electron density and its weak hybridisation with buried atomic orbitals evidence the quantum and pure nature of electrons, that exhibit a polarized liquid phase as demonstrated by our spin-dependent measurement. Further, upon enhancing the electron correlation strength, the dynamics of quantum electrons changes to that of non-Fermi liquid along with an anomalous band deformation, suggestive of a transition to a hexatic liquid crystal phase. Our findings cultivate the frontier of quantum electron systems, and serve as a platform for exploring correlated electronic phases in a pure fashion.Electron phases, ranging from gas to liquid and solid, are foundational in physics, chemistry, and materials science. Understanding the characteristics of each electron phase, both

No abstract

Pure quantum electrons render intriguing correlated electronic phases by virtue of quantum fluctuations in addition to an exclusive electron-electron interaction. To realise such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid, which spreads up to ~ 3 Å in the vacuum on the surface of electride crystal. An extremely high electron density and its scant hybridization with underneath atomic orbitals evidence quantum and pure nature of electrons, exhibiting polarized liquid phase demonstrated by spin-dependent measurement. Further, upon reducing the density, the dynamics of quantum electrons drastically changes to that of non-Fermi liquid along with an anomalous band deformation, manifesting a possible transition to a hexatic liquid crystalline phase. Our findings cultivate the frontier of quantum electron systems, which serve as an ideal platform for exploring the correlated electronic phases in a pure manner.

Temperature dependence of magnetic moment (m−T) and the magnetization (M− ) at 5 K and 20 K of the in situ processed MgB 2 bulk pellets with/without carbon (C) doping were examined. The superconducting critical temperature (T c ), the superconducting transition width (∆T) and the critical current density (J c ) were estimated for ten test samples taken from the MgB 2 bulk pellets. The reliable m−T characteristics associated with the uniform MgB 2 formation were obtained for both MgB 2 pellets. The T c s and ∆Ts of all test samples of the undoped MgB 2 were the same each other as 37.5 K and 1.5 K, respectively. The T c s and ∆Ts of the C-doped MgB 2 were 36.5 K and 2.5 K, respectively. Unlike the m−T characteristics, there existed the difference among the M−H curves of the test samples, which might be caused by the microstructure variation. In spite of the slight T c decrease, the C doping was effective in enhancing the J c at 5 K.