阅读说明：本技术 一种高质量的拓扑半金属InBi生长方法 (High-quality topological semi-metal InBi growth method ) 是由 王学锋 李焱 张敏昊 钮伟 于 2020-06-18 设计创作，主要内容包括：本发明公开了一种利用高温回转炉生长高质量拓扑半金属InBi单晶的方法,块体是In、Bi元素以1:1化学计量比形成的化合物,是具有第二类狄拉克点的拓扑半金属材料,通过低场磁输运测试,块体单晶具有大的载流子浓度1018cm-3和高迁移率,14T未饱和磁阻MR的值到达12000％,低温1.5K、高场60T出项明显振荡；同时角分辨光电子能谱(ARPES)和X射线衍射光谱仪(XRD)的表征,证明了其很高的质量,ARPES分析在ΓXΓ和MXM方向上发现2条nodal-line。制备方法是高温融合后,以1℃/min的速率缓慢降温至室温结晶形成大块单晶,所获得的单晶表征ARPES和XRD信号均与文献记载相吻合,确定为高质量的块体,同时材料制备参数易调整,设备简单,易操作,生长过程可控,工艺重复性好,具有较高的制备效率。(The invention discloses a method for growing high-quality topological semi-metal InBi single crystals by using a high-temperature rotary furnace, wherein a block is a compound formed by In and Bi elements In a 1:1 stoichiometric ratio, and is a topological semi-metal material with a second class of Dirac points, and through a low-field magnetic transport test, the block single crystal has large carrier concentration of 1018cm & lt-3 & gt and high mobility, the value of 14T unsaturated magnetic resistance MR reaches 12000%, and the low-temperature 1.5K and high-field 60T obviously oscillate; the high quality was demonstrated by simultaneous characterization of angle-resolved photoelectron spectroscopy (ARPES) and X-ray diffraction spectroscopy (XRD), the ARPES analysis finding 2 nodal-lines in the X and MXM directions. The preparation method is that after high-temperature fusion, the temperature is slowly reduced to room temperature at the speed of 1 ℃/min to crystallize to form bulk single crystals, the characterization ARPES and XRD signals of the obtained single crystals are identical with those recorded in the literature and are determined to be high-quality blocks, and meanwhile, the preparation parameters of the material are easy to adjust, the equipment is simple, the operation is easy, the growth process is controllable, the process repeatability is good, and the preparation efficiency is higher.)

1. A high-quality topological semi-metal InBi growth method is characterized in that: the method comprises the following steps:

step 1: mixing In powder and Bi powder In a ratio of 1:1, putting the mixture into a small quartz tube, pumping the air pressure to be lower than 0.1mbar by using a mechanical pump, and sealing the tube;

step 2: placing the quartz tube after tube sealing into a high-temperature tube furnace, obliquely placing the quartz tube to enable the material end to be lower than the tube opening so as to be convenient for growing large single crystals, and raising the temperature to 800 ℃ within 24 hours;

and step 3: keeping the temperature at 800 ℃ for 48h, and slowly rotating the tube furnace in the period;

and 4, step 4: after the step 3, slowly cooling to room temperature at the speed of 1 ℃/min and then taking out.

2. The high quality topological semi-metallic InBi growth method of claim 1, wherein: the InBi block is a compound formed by In and Bi In a chemical element ratio of 1:1, has high mobility and carrier concentration, is silvery white In color and single crystal size of cm level, and can be stripped into a sheet shape with a flat and thin surface.

Technical Field

The invention belongs to the technical field of topological semi-metal materials, and particularly relates to representation of a second Dirac point, related structural characteristics and application of a magnetic storage technology.

Background

In recent years, research on topological insulators has shown that insulators can be further subdivided into general insulators and topological insulators. Topological insulators can exhibit quantum phenomena and physical properties completely different from those of general insulators, such as topologically protected surface states, anti-weak localization, quantum spin/abnormal hall effects, and the like. A plurality of novel physical phenomena exist in the emerging topological insulator and the first and second kinds of Dirac material systems thereof, topological node semimetals (such as zirconium silicon sulfur ZrSiS) show different properties on physical characteristics, and the materials have wide and profound influence in the multidisciplinary fields of condensed state physics, quantum material science and the like, thereby providing a new carrier and basis for the physical property research of topological materials and the discovery of novel topological materials.

Conventional topological dirac semimetal materials (e.g., cadmium arsenide Cd3As2) have linear contacts of the conduction and valence bands of their bulk phases at discrete points in momentum space to form dirac points. A recent new dirac semimetal material InBi has received much attention and research to possess robust dirac nodes (bulk discrete dirac point extension becomes a one-dimensional line). The high-quality InBi single crystal block is prepared by a tube furnace and is subjected to electromagnetic transport research, and the result shows that the large carrier concentration and the high mobility of the InBi single crystal block and 60T unsaturated giant magnetoresistance can be used for the magnetic storage technology. On the basis of the test, the angular resolution photoelectron spectroscopy (APRES) is also carried out, 2 nodal lines are respectively found in the X direction and the MXM direction, and the nature of the topological node semimetal is confirmed. The Dirac point structure of InBi has great research and application prospects in the field of condensed state physics, and the research on the growth method of the Dirac point structure has great research value in obtaining a high-quality large-size block. The invention introduces a method for growing large-size high-quality InBi by using a tube furnace method and provides data on relevant characteristics of the InBi.

Disclosure of Invention

The invention aims to provide a preparation method for conveniently growing a large-block high-quality InBi single crystal and characterization of relevant properties of the block, wherein the InBi single crystal has a large carrier concentration of 1018cm-3 and a large mobility (10000cm2V-1s-1) and a 14T unsaturated MR value of 12000% through a low-field PPMS test.

The invention is realized by the following technical scheme:

a high-quality topological semi-metal InBi growth method comprises the following steps:

step 1: mixing In powder and Bi powder In a ratio of 1:1, putting the mixture into a small quartz tube, pumping the air pressure to be lower than 0.1mbar by using a mechanical pump, and sealing the tube;

step 2: placing the quartz tube after tube sealing into a high-temperature tube furnace, obliquely placing the quartz tube to enable the material end to be lower than the tube opening so as to be convenient for growing large single crystals, and raising the temperature to 800 ℃ within 24 hours;

and step 3: keeping the temperature at 800 ℃ for 48h, and slowly rotating the tube furnace in the period;

and 4, step 4: after the step 3, slowly cooling to room temperature at the speed of 1 ℃/min and then taking out.

As an improvement of the technical scheme, the InBi block is formed by forming a compound by using In and Bi In a chemical element ratio of 1:1, has high mobility and carrier concentration, is silvery white In color, is single-crystal-size cm-level, and can be stripped into a sheet shape with a flat and thin surface.

The invention has the beneficial effects that:

the growth method has the advantages of simple equipment, easy operation, easy adjustment of preparation parameters, good process repeatability and higher preparation efficiency, and can be expanded to the preparation of other high-quality topological semi-metal materials.

The invention provides a method for preparing a high-quality InBi block, the material is one of second class Dirac topological semi-metals, has very high physical research significance, and the growth method is a simple and feasible block material preparation technology at present; the invention prepares the InBi single crystal block with higher mobility and carrier concentration by utilizing high-temperature complete fusion and slow cooling crystallization, and improves the size of the material, thereby being beneficial to further researching and developing related topological materials.

The material obtained by the invention is a high-quality monocrystalline block, is silvery white in color, and is proved to have high quality through characterization of XRD and angle-resolved photoelectron spectroscopy (ARPES), 2 nodal-lines are found in X and MXM directions through ARPES analysis, and high mobility and large carrier concentration are shown through low-field and high-field magnetic transport tests.

Drawings

FIG. 1 is a schematic diagram of an apparatus of a high temperature rotary furnace;

FIG. 2 is an X-ray diffraction pattern of an InBi mass;

FIG. 3 is an angle-resolved photoelectron spectrum at an energy of 28eV for an InBi single crystal;

FIG. 4 is a low temperature high field transport resistance map of an InBi block;

FIG. 5 is a low temperature high field RT transport map of an InBi block, showing good metallicity;

FIG. 6 is a plot of the angular transport at 1.5K for an InBi mass, with (0 degree) oscillation evident when the magnetic field is perpendicular to the sample surface.

Detailed Description