Crystal growth and magnetic structure of MnBi2Te4

Abstract

Millimeter-sized MnBi2Te4 single crystals are grown out of a Bi-Te flux and characterized using magnetic, transport, scanning tunneling microscopy and spectroscopy measurements. The magnetic structure of MnBi2Te4 below TN is determined by powder and single crystal neutron diffraction measurements. Below TN =24 K, Mn 2+ moments order ferromagnetically in the ab-plane but antiferromagnetically along the crystallographic c-axis. The ordered moment is 4.04(13)µB/Mn at 10 K and aligned along the crystallographic c-axis in an A-type antiferromagnetic order. The electrical resistivity drops upon cooling across TN or when going across the metamagnetic transition in increasing magnetic fields below TN . A critical scattering effect is observed in the vicinity of TN in the temperature dependence of thermal conductivity. However, a linear temperature dependence is observed for the thermopower in the temperature range 2 K≤T≤300 K without any anomaly around TN . Fine tuning of the magnetism and/or electronic band structure is needed for the proposed topological properties of this compound. The growth protocol reported in this work might be applied to grow high quality crystals where the electronic band structure and magnetism can be finely tuned by chemical substitutions.

Topological Electronic Structure and Its Temperature Evolution in Antiferromagnetic Topological Insulator MnBi2Te4

“…MnBi2Te4 crystallizes into a rhombohedral lattice with space group of R3 ̅ m [19,28]. It exhibits a layered structure by staking van der Waals septuple Te-Bi-Te-Mn-Te-Bi-Te layers, which has an extra Mn-Te layer sandwiched at the middle of the well-known quintuple-layer of Bi2Te3, as shown in Fig.…”

Experimental Observation of the Gate-Controlled Reversal of the Anomalous Hall Effect in the Intrinsic Magnetic Topological Insulator MnBi2Te4 Device

“…The pursuit of high quality quantum anomalous Hall [1][2][3][4][5] devices ignited the upsurge of intrinsic magnetic topological insulators (IMTI) of MnBi 2 Te 4 (MBT) [6][7][8][9][10][11][12][13][14] to avoid the possibly low strength of doped [15][16][17] or proximity-induced [18,19] magnetism in previous magnetic topological insulators [20]. It was noticed with a surface band and predicted to be IMTI with a sizeable magnetic gap by several groups [8][9][10].…”

Chern-Simons superconductors and their instabilities

“…Both of the above phenomena have received great attention and evoked fundamental developments, analytically and numerically, in strongly-correlated condensed matter systems. Furthermore, much progress was recently achieved in the understnding of AFM topological materials [65][66][67][68], such as the AFM topological insulator (TI) MnTe 2 Bi 4 [69][70][71][72][73][74][75][76][77], whose topological surface states and the quantized anomalous Hall effect have been experimentally verified. Similar achievements also include AFM topological semimetals (TSMs) [78][79][80][81].…”

“…1, it then becomes possible to derive a possibly "global" theory to depict the evolution of the system from the Néel AFM to QSLs and allows a new method to investigate the unconventional phase transitions. We note that this scheme also has potential applications in the field of magnetic topological materials such as the magnetic TIs [69][70][71][72][73][74][75][76][77] and magnetic TSMs [78][79][80][114][115][116][117]. For an electronic system with significant spin-orbit-coupling and antiferromagnetism, one can apply the scheme and map the model Hamiltonian to a gauge field theory consisting of two flavors of matter fields.…”