List of Bulk Samples Available

Bi₂Se₃

Bi₂Se₃ is a well-known topological insulator. This system has rhombohedral layered crystal structure with quintuple layers (QLs) ordered in a Se-Bi-Se-Bi-Se sequence along the c-axis. The QLs weakly interact through the van der Waals forces and therefore the materials cleave easily between QLs. The typical n-type charge carrier density and Hall mobility are about 10¹⁸ cm^-3 and 700 cm²/Vs at room temperature.

Bi_1.98Ca_0.02Se₃

Bi₂Se₃ is a topological insulator with n-type carrier charge due to selenium self-vacancies. p-type Bi₂Se₃ single crystal is synthesized by substituting calcium on bismuth site to compensate the electrons created by the selenium vacancies. The typical charge carrier density and Hall mobility are about 10¹⁸ cm^-3 and 2000 cm²/Vs at 2K, respectively. The Fermi level of the system located in the bulk bandgap, suggested from the Scanning Tunneling Spectroscopy (STS) spectra, the system suitable for the topological surface states study.

(Bi,Sb)₂Te₃

Bi₂Te₃ is one of the good thermoelectric materials and has been commercialized for a wide range of applications in power generation and refrigeration. By alloying the Bi₂Te₃ and Sb₂Te₃, it allows us to fine-tune the carrier density as well as the reduction in lattice thermal conductivity.

Fe-doped Bi₂Se₃

Time-reversal symmetry (TRS) can be broken when a magnetic order is introduced into topological insulators and resulting the non-trivial topological surface drives into a new massive Dirac fermion state. By intercalating iron into Bi₂Se₃ quintuple layers, the magnetic ground state of the system is antifferomagentic with T_N = 100K. However, this system is also a metamagentic system, where the magnetic properties of the system can be driven into ferromagnetic by external magnetic field, Hc ~ 400 Oe. The typical n-type charge carrier density and Hall mobility are about 10¹⁹ cm^-3 and 1700 cm²/Vs at 2K.

MnBi₂Te₄

MnBi₂Te₄ has recently been established as the first intrinsic antiferromagnetic (AFM) topological insulator (TI) with T_N = 25K. Several exotic properties, such as quantum anomalous Hall effect (QAHE), axion insulator, and layered Hall effect have been experimentally observed in its 2D limit.

Mn(Bi_1-xSb_x)₂Te₄

The as-grown MnBi₂Te₄ is heavily electron-doped possible due to non-stoichiometry or antisite defects.  By partially substituting Sb for Bi, its Fermi level not only can be tuned from the bulk conduction band (electron-doped) to the bulk valence band (hole-doped) but also its carrier mobility is dramatically enhanced. It makes the system suitable to realize the proposed topological state, such as idea Weyl semimetal. We capable of growing Mn(Bi_1-xSb_x)₂Te₄ from x = 0 to x = 1.0

MnBi₄Te₇

MnBi₄Te₇ is an antiferromagnetic topological insulator (T_N = 13K), with the building block of septuple layer MnBi₂Te₄ and a quintuple layer of Bi₂Te₃. Due to the weak interlayer magnetic coupling as compared to MnBi₂Te₄, an antiferromagnetic with a small saturation field is achieved.

Mn(Bi_1-xSb_x)₆Te₁₀

Via controlling the parameters of growth condition, we can realize both FM state and AFM state in MnBi₆Te₁₀, without any doping for the first time. The ferromagnetic transition temperature is T_C ~ 13K. Similar to MnBi₄Te₇, MnBi₆Te₁₀ consists of the building block of septuple layer MnBi₂Te₄ and two quintuple layer of Bi₂Te₃. Theory predicts that a variety of exotic topological states, such as quantum anomalous Hall insualtor, Mobius insulator, high order topological state, quantum spin Hall effect, and hinged quantum spin hall effect can be realized. We capable of growing Mn(Bi_1-xSb_x)₆Te₁₀ from x = 0 to x = 0.3

α-In₂Se₃

α-In₂Se₃ is a layered transition metal chalcogenide featuring a van de Waals interlayer coupling and an energy gap of 1.4 eV. This material was predicted to be a ferroelectric material in bulk.

SnSe₂

SnSe is a transition metal dichalcogenide. The system can be exfoliated into thin 2D layers due to the weakly-bounded layered structure. The typical n-type charge carrier density and Hall mobility are about 10¹⁷ cm^-3 and 30 cm²/Vs at room temperature.

InSe

InSe is a mono-chalcogenides layered compound. It receives great interest due to the exceptional properties, such as high electron mobility, tunable absorption, and extremely strong photoresponse. XRD pattern suggests the crystal is in β-phase.

SnSe

SnSe is a semiconductor with a bulk indirect bandgap of 0.9eV. Due to its low thermal conductivity as well as electrical conductivity, it is one of the most efficient thermoelectric materials.

MoS₂

MoS₂ is a well-known transition metal dichalcogenide and recently experimental demonstrates the gate-induced superconductivity in exfoliated MoS₂ multilayers. The typical charge carrier density for MoS₂ sample is about 10¹⁵.

Nb-doped MoS₂

MoS₂ is a well-known transition metal dichalcogenide and recently experimental demonstrates the gate-induced superconductivity in exfoliated MoS₂ multilayers. p-type MoS₂ can be synthesized by niobium doping. The typical p-type charge carrier density and Hall mobility of our Nb-doped MoS₂ sample are about 10¹⁸ to 10¹⁹ cm^-3 and 15 cm²/Vs at room temperature.

MoSe₂

MoSe₂ is a semiconductor with a bulk indirect bandgap of 1.1 eV.

1T-MoTe_1.8S_0.2

1T-MoTe_1.8S_0.2 is a superconductors with T_c~1.3K

WS₂

Bulk WS₂ forms dark gray hexagonal crystals with a layered structure. Like the closely related MoS₂, WS₂ is a semiconductor with a bulk indirect bandgap of ~1.35eV

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WSe₂

WSe₂ is a semiconductor with a bulk indirect bandgap of ~1.2eV.

1T’ and 1Td-WTe₂

WTe₂ is a well-known transition metal dichalcogenide. It is also a type-II Weyl semimetal. The typical n-type charge carrier density and Hall mobility are about 10²⁰ cm^-3 and 40 cm²/Vs at room temperature.

(W_1-xMo_x)Se₂

(W_1-xMo_x)Se₂ is a semiconductor. The currently available alloy is rich in Tungsten with 10% Mo.

NbS₂

NbS₂ is a metal with the emergence of a superconducting state at T_c ~ 6 K and a charge density waves (CDW) system.

NbSe₂

NbSe₂ is a metal with the emergence of a supercoucting state at T_c ~ 7.2 K and a charge density waves (CDW) state at T_cdw ~ 33 K.

VSe₂

VSe₂ has a metallic behavior in the resistivity measurement with a charge density wave below 110K. This material receives great interest due to the observation of ferromagnetic ordered in monolayer at room temperature.

HfS₂

HS₂ is a semiconductor with a bulk indirect bandgap of ~2eV.

HfSe₂

HSe₂ is a semiconductor with a bulk indirect bandgap of ~1.1eV.

ReSe₂

ReSe₂ is a semiconductor with band gap ~1.1eV

TaS₂

TaS₂ shows an incommensurate charge density waves (CDW) transition among ~80K and become superconductor at T_c~1K.

TaSe₂

2H-TaSe₂ is a metal, which shows the incommensurate Charge density waves (CDW) transition at 120K. It also become a superconductor below 0.1K.

TiS₂

TiS₂ is van der Waals semimetal

TiSe₂

TiSe₂ is a semimetal with CDW around 202 K.

ZrS₂

This flake was formed in an evacuated quartz ampoule by CVT synthesis method. The temperature of the source was approximately 900 °C and the crystals formed at the ampoule end that was heated to approximately 800 °C. The formation of ZrS₂ is confirmed by hexagonal crystal features and Raman spectrum that matches literature reports for the material.

ZrSe₂

This flake was formed in an evacuated quartz ampoule by CVT synthesis method. The temperature of the source was approximately 900 °C and the crystals formed at the ampoule end that was heated to approximately 800 °C for 200 hours. The formation of ZrSe₂ is confirmed by hexagonal crystal features and Raman spectrum that matches literature reports for the material.

Zr(Se_1-xS_x)₂

This flake was formed in an evacuated quartz ampoule by CVT synthesis method. The temperature of the source was approximately 900 °C and the crystals formed at the ampoule end that was heated to approximately 800 °C for 200 hours. The loaded source weight ratios of Zr, Se and S powder was 1:0.5:1.5 respectively. The flake is layered and a freshly cleaved surface was used for EDS composition analysis. It was found through normalized atomic % content the crystal contains an S:Se ratio of 1.52:0.48 which is very close to the source loading stoichiometry.

MnPS₃

MnPS3 is a van der Waals, antiferromagnetic insulator material with T_c ~ 78 K.

Cr₂Ge₂Te₆

Cr₂Ge₂Te₆ is a ferromagnetic insulator with a Curie temperature T_c of 61 K and is an insulator below T <100 K.

AgVP₂Se₆

AgVP₂Se₆ is a quaternary layered ferromagnetic semiconductor (T_c ~ 18.5K) with chiral structure. The Se-Se are bonded via weak van der Waals, allowing layers to be easily exfoliated. This metal thiophosphate material has been predicted to host the quantum anomalous Hall effect and allow for spontaneous valley splitting and valley pseudospin field effect transistor in its 2D limit.

CrTe₂

CrTe₂ is a metastable layered magnetic compound with T_c at 310K. Due to the weak van der Waals bonding, the layers can be easily exfoliated. It thus offer new opportunities to study spintronic devices at room temperature.

NiI₂

A spin induced multiferroic materials (T_c = 60 K). Recently, ferroelectricity was discovered in a monolayer limit. Thus, potential candidate for future spin transport study with electrical manipulation. It can be easily exfoliate due to the van der Walls structure.

CrSBr

Recently discovered van der Waals magnetic semiconductor. Easy plane antiferromagnetic transition T_N = 142 K). Can be easily exfoliate and study the spin tunnel junction in the monolayer limit.

MnAl₂Te₄

Polar bulk magnetic semiconductor. Observed magnetodielectric response. A potential candidate for further exploration electronic structure and magnetotransport properties.

FeSe_0.45Te_0.55

FeSe_0.45Te_0.55 is an iron based superconductors with T_c~14K

Sm₂Te₅

Sm₂Te₅ is a rare-earth polytelluride that has two separate charge density wave distortions of its square nets of tellurium. Due to the weak van der Waals bonding, the layers can be easily exfoliated.

CeTe₃

CeTe₃ is one of the quasi-two-dimensional compounds with two square Te-sheets that are stacked along the b-axis. Due to its quasi 2D nature of the Te-sheet, the charge density wave is formed at room temperature.

TbTe₃

TbTe₃ is a metal and shows CDW transition at 335K. It also exhibits a long range incommensurate magnetic order emerges at 5.78K

NdTe₃

NdTe₃ is an isostructural compound to the TbTe₃. It shows an AFM magnetic transition at 3K.