arXiv subjects

Bingqi Si

Publications and source records attributed to Bingqi Si.

3 recordsLinked to original sources

arXiv2013

Sr and Mn co-doped LaCuSO: A wide band gap oxide diluted magnetic semiconductor with TC around 200K

Here we report the synthesis of a bulk oxide diluted magnetic semiconductor (DMS) system La1-xSrxCu0.925Mn0.075SO (x=0, 0.025, 0.05, 0.075, and 0.1). As a wide band gap p-type oxide semiconductor, LaCuSO satisfies all the conditions forecasted theoretically to be a room temperature DMS. The Curie temperature (TC) is around 200K as x>0.05, which is among the highest TC record of known bulk DMS materials up to now. The system provides a rare example of oxide DMS system with p-type conduction, which is important for formation of high temperature spintronic devices.

cond-mat.mtrl-sci↗

arXiv2013

Li$_2$RhO$_3$: A spin-glassy relativistic Mott insulator

Motivated by the rich interplay among electronic correlation, spin-orbit coupling (SOC), crystal-field splitting, and geometric frustrations in the honeycomb-like lattice, we systematically investigated the electronic and magnetic properties of Li$_2$RhO$_3$. The material is semiconducting with a narrow band gap of $Δ\sim$78 meV, and its temperature dependence of resistivity conforms to 3D variable range hopping mechanism. No long-range magnetic ordering was found down to 0.5 K, due to the geometric frustrations. Instead, single atomic spin-glass behavior below the spin-freezing temperature ($\sim$6 K) was observed and its spin dynamics obeys the universal critical slowing down scaling law. First principle calculations suggested it to be a relativistic Mott insulator mediated by both electronic correlation and SOC. With moderate strength of electronic correlation and SOC, our results shed new light to the research of Heisenberg-Kitaev model in realistic materials.

cond-mat.str-el↗

arXiv2012

Magnetic property and crystalline electric field effect in ThCr$_2$Si$_2$-type CeNi$_2$As$_2$

Millimeter sized ThCr$_2$Si$_2$-type CeNi$_2$As$_2$ single crystal was synthesized by NaAs flux method and its physical properties were investigated by magnetization, transport and specific heat measurements. In contrast to the previously reported CaBe$_2$Ge$_2$-type CeNi$_2$As$_2$, the ThCr$_2$Si$_2$-type CeNi$_2$As$_2$ is a highly anisotropic uniaxial antiferromagnet with the transition temperature $T_N$=4.8 K. A field induced spin flop transition was seen below $T_N$ when the applied $\textbf{B}$ is parallel to the $\textbf{c}$-axis, the magnetic easy axis, together with a huge frustration parameter $f=θ_W/T_N$. A pronounced Schottky-like anomaly in specific heat was also found around 160 K, which could be attributed to the crystalline electric field effect with the excitation energies being fitted to $Δ_1=$325 K and $Δ_2=$520 K, respectively. Moreover, the in-plane resistivity anisotropy and low temperature X-ray diffractions suggest that this compound is a rare example exhibiting a possible structure distortion induced by the $4f$-electron magnetic frustration.

cond-mat.str-el↗