Cryogen-free dilution refrigerator with 14T magnet for high-field studies of quantum materials

量子材料是在实验室中设计的新系统，它具有足够强的电子相互作用，可以显示量子现象，如超导性，相关绝缘状态和磁性，具有巨大的技术应用。当电子相互作用超过系统的热波动时，即在毫开尔文温度下，就会出现这些现象。实验上，这些温度是在稀释冰箱系统中达到的。因此，我们的目标是在LMU的实验能力中增加这样一个稀释冰箱，其基本温度为10 mK（稳定性低于5mK），并配备14T超导磁体。LMU目前的设备中没有这个系统，它将专门用于上述量子材料的研究。这次收购对于确保我们机构的竞争地位至关重要，更确切地说，是固态物理主席在这个及时的主题上的竞争地位。超高的14T磁场将允许我们为材料引入新的量子化能量尺度，从而调整电子相互作用。特别是，这个场将足够高，可以将各种量子材料的所有电子载流子浓缩到一个单一的能级，从而使电子光谱变得类似于对扰动高度敏感的一维系统。达到这个超量子极限允许出现新的现象，如电荷/自旋密度波和量子霍尔效应。因此，这个冰箱系统将在LMU开辟一个全新的研究轴。我们将通过48条高滤波直流传输线来探测电子对温度和场约束的响应，这些传输线旨在抑制电子的电磁加热，并将输出集成在我们的测量装置中，该装置由一系列直流前置放大器和锁定放大器组成。附加的样品旋转器将扩大操作面积，由此磁场可以相对于样品表面任意施加。快速加载机制通过大大减少加载时间来优化我们对该系统的使用至关重要。最后，我们希望购买一个无低温系统，因为它使用简单，因为我们计划在LMU和慕尼黑量子谷倡议的几个主席之间授予访问设备的权利，并且考虑到液氦价格不断上涨，它允许长期经济。

Quantum materials are novel systems, engineered in laboratories, which host strong enough electronic interactions to display quantum phenomena such as superconductivity, correlated insulating states and magnetism with tremendous technological applications. These phenomena emerge when the electronic interaction dominate over the thermal fluctuations of the system, i.e. at milliKelvin temperatures. Experimentally, these temperatures are reached in dilution refrigerator systems. Consequently, we aim to add such a dilution refrigerator, capable of a base temperature of 10 mK (and stability below 5mK) and equipped with a 14T superconducting magnet, to the LMU’s experimental capabilities. This system, absent from the current apparatus of the LMU, will be dedicated to the study of said quantum materials. This acquisition is paramount to secure a competitive position for our institution, and more precisely its Chair of Solid State Physics, on this timely subject. The ultra-high 14T magnetic field will allow us to introduce a new quantizing energy scale to the material, and thus to tune the electronic interaction. In particular, this field will be high enough to condense all the electronic carriers of a variety of quantum materials into a single energy level, causing the electronic spectrum to become analogous to a one-dimensional system which is highly sensitive to pertubations. Attaining this ultra-quantum limit permits the emergence of novel phenomena such as charge/spin density waves and quantum Hall effect. This refrigerator system will thus open completely new axis of research at the LMU. We will probe the electronic response to the temperature and field constraints through 48 highly-filtered DC transmission lines designed to suppress electromagnetic heating of the electrons with an output integrated in our measurement setup made of an array of DC pre-amplifiers and lock-in amplifiers. The additional sample rotator will expand the operational area, whereby the magnetic field can be applied arbitrary with respect to the sample surface. The fast loading mechanism is crucial to optimize our usage of this system by greatly reducing loading times. Finally, we wish to buy a cryogen-free system both for its simplicity of usage, as we plan to grant access to the equipment across several chairs of the LMU as well as the Munich Quantum Valley initiative, and for the long-term economies it permits in light of the ever increasing price of liquid helium.