Quantum computing heat recuperator and method of preparation
Patent Information
- Application Number
- CN202611133415.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-29
- Publication Date
- 2026-10-30
AI Technical Summary
低温下产生的废热增加了布线、噪声与系统复杂度，阻碍了量子计算的规模化扩展
[0022]本公开的热回收器件，利用拓扑材料中的层间可调的贝利曲率，调控反常能斯特效应，将低温环境中的废热回收并转换为电信号，以实现在量子计算领域的热管理与能量回收。
Smart Images
Figure CN123022109A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of quantum computing and microelectronics technology, and particularly relates to a quantum computing heat recovery device and its preparation method. Background Technology
[0002] The Nernst effect is a transverse thermoelectric conversion effect. When a longitudinal temperature gradient ∇T exists in a material, a transverse electric field (potential difference) is generated in the direction perpendicular to ∇T. The anomalous Nernst effect (ANE), on the other hand, is a transverse thermoelectric response driven by the Berry curvature (i.e., the geometric phase in momentum space) of the material's energy bands under zero external magnetic field conditions. Its magnitude is proportional to the Berry curvature distribution near the Fermi surface. Unlike the conventional Nernst effect, which depends on an external magnetic field, the ANE operates under zero magnetic field conditions, thus offering unique advantages in micro / nano-scale thermal management and energy recovery. Currently, materials known to have large ANEs are mainly ferromagnetic topological materials, such as Co₂MnGa, Mn₃Sn, and Co₃Sn₂S₂.
[0003] In the field of quantum computing, cryogenic thermal management is one of the key challenges in realizing scalable quantum processors. Waste heat generated at low temperatures increases wiring, noise, and system complexity, hindering the scalability of quantum computing. Specifically, waste heat in dilution refrigerators mainly originates from coaxial wiring, attenuators, circulators, cryogenic amplifiers (HEMTs), and ohmic dissipation on qubit control / readout lines. This heat is concentrated in the mK–4K temperature range, where the cooling power is only on the order of microwatts to milliwatts. Therefore, waste heat removal becomes a bottleneck limiting the expansion of the number of qubits. Thus, transverse thermoelectric effects (such as the anomalous Nernst effect) can be used to directly convert localized waste heat into electrical signals, simultaneously achieving thermal management and energy recovery.
[0004] Currently, there are two main types of devices used for thermoelectric energy recovery. The first type is based on the longitudinal Seebeck effect, where the heat flow direction is parallel to the voltage direction. The second type is based on the transverse anomalous Nernst effect, where the voltage direction is perpendicular to the temperature gradient direction. Summary of the Invention
[0005] One aspect of this disclosure is a quantum computing heat recovery and conversion device based on topological materials, the device comprising:
[0006] Bottom grid layer;
[0007] A first insulating layer is grown on the bottom gate layer;
[0008] A thermoelectric conversion layer is grown on the first insulating layer;
[0009] A pair of transverse electrodes is grown on the first insulating layer and electrically connected to the thermoelectric conversion layer;
[0010] The bottom gate layer applies a first out-of-plane displacement field to the thermoelectric conversion layer through the first insulating layer to switch and regulate the anomalous Nernst effect of the heat recovery unit.
[0011] Furthermore, the heat recovery device also includes,
[0012] A second insulating layer is grown on the thermoelectric conversion layer and the lateral electrode pair;
[0013] Top grid layer;
[0014] The top gate layer applies a second out-of-plane displacement field to the thermoelectric conversion layer through the second insulating layer.
[0015] The thermoelectric conversion layer is a lateral thermoelectric conversion layer based on topological materials.
[0016] One aspect of this disclosure is a method for fabricating a quantum computing heat recovery device, the method comprising the following steps:
[0017] The first insulating layer is grown on the bottom gate layer.
[0018] A thermoelectric conversion layer of topological antiferromagnetic material and a pair of transverse electrodes connected to the thermoelectric conversion layer are grown on the first insulating layer.
[0019] A second insulating layer is grown on the lateral electrode pair and the thermoelectric conversion layer;
[0020] A top gate layer is grown on the second insulating layer;
[0021] Connect the grid voltage source and the external circuit, which is used to read the transverse Nernst voltage signal or to store energy.
[0022] The heat recovery device disclosed herein utilizes the tunable Berry curvature between layers in a topological material to modulate the anomalous Nernst effect, recovering waste heat from a low-temperature environment and converting it into an electrical signal, thereby realizing thermal management and energy recovery in the field of quantum computing. Attached Figure Description
[0023] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:
[0024] Figure 1 An exploded schematic diagram of a quantum computing heat recovery device based on topological materials according to one embodiment of the present disclosure.
[0025] Figure 2 A graph showing the relationship between the transverse Nernst signal and the gate voltage of a heat recovery device according to one embodiment of the present disclosure.
[0026] Figure 3 The relationship between the transverse Nernst signal and the out-of-plane electric field εE of a heat recovery device according to one embodiment of the present disclosure.
[0027] Figure 4. Switching frequency diagram of the anomalous Nernst signal of a heat recovery device according to one embodiment of the present disclosure.
[0028] Figure 5. A graph showing the relationship between the anomalous Nernst signal of a heat recovery device according to one embodiment of the present disclosure and the applied magnetic field.
[0029] Wherein, 1—bottom gate layer, 2—first insulating layer (bottom gate dielectric layer), 3—topological material thermoelectric conversion layer, 4—lateral electrode pair, 501—first out-of-plane displacement field (first gate voltage), 502—second out-of-plane displacement field (second gate voltage), 6—second insulating layer (top gate dielectric layer), 7—top gate layer. Detailed Implementation
[0030] This disclosure, through research on existing thermoelectric recovery and transverse thermoelectric devices, reveals that these devices mainly suffer from the following shortcomings:
[0031] a) Devices based on the longitudinal Seebeck effect have a voltage output direction parallel to the heat flow direction, making it difficult to achieve directional heat flow guidance and local heat extraction. They are also more sensitive to electrode contact resistance and heat shunting loss, which is not conducive to micro-nano scale on-chip integration.
[0032] b) Most existing materials with a large Nernst effect are ferromagnetic, possessing a net magnetic moment and generating stray magnetic fields. This conflicts with the stringent requirements of superconducting qubits for the magnetic environment (requiring strict magnetic shielding and zero or extremely low residual magnetic fields), making them difficult to integrate with quantum processors.
[0033] c) The Berry curvature of existing anomalous Nernst devices (ANEs) cannot be electrically switched or continuously adjusted (i.e., they lack controllable "on / off" and sign-flipping capabilities), resulting in limited functionality. This is because: firstly, the aforementioned large ANE materials are all bulk or thick-film metallic ferromagnets with carrier concentrations as high as 10-1. 22 cm -3 First, the Thomas-Fermi shield is only about 0.1 nm long, meaning the gate electric field can only penetrate one or two atomic layers of the surface, making it impossible to modulate the transport channels within the bulk. Second, its Bélix curvature is determined by both spontaneous magnetization and spin-orbit coupling, and is an intrinsic property in momentum space. The sign of the ANE can only be changed by reversing magnetization with an external magnetic field, not by continuously adjusting its magnitude with an electric field. Therefore, the thermoelectric output of such devices is essentially fixed.
[0034] d) At low temperatures (especially in the extremely low temperature range required for quantum computing), the anomalous Nernst signal of most materials is very small, making it difficult to obtain a large and reliably tunable anomalous Nernst response at low temperatures.
[0035] This disclosure proposes a quantum computing heat recovery device based on topological materials. The device uses a topological antiferromagnetic material as the lateral thermoelectric conversion layer, enabling the recovery and conversion of waste heat (temperature gradient) generated by the quantum computing chip into a lateral voltage signal via the anomalous Nernst effect under low-temperature, zero-external magnetic field conditions. Furthermore, its thermoelectric response can be modulated by an out-of-plane electric field (gate voltage), thus achieving a fully electrical switch for heat recovery. In this disclosure, "fully electrical switch" means that by applying a voltage to the gate (i.e., applying an out-of-plane displacement field), the anomalous Nernst response of the device can be reversibly switched between an on and off state, with continuous adjustment of amplitude and reversal of polarity. This process does not require an external magnetic field and does not rely on any non-electrical means such as mechanical, optical, or temperature adjustments.
[0036] The core physical mechanism utilized in this disclosure is that the interlayer Bailey curvature of the material can be tuned by applying an external electric field, thereby achieving a tunable anomalous Nernst effect at low temperatures. Since the device operates under zero external magnetic field, it also exhibits robustness to external stray magnetic fields (its anomalous Nernst response remains essentially unchanged under stray magnetic fields as high as approximately 2 T), such as... Figure 5 As shown, at T = 2 K, the external magnetic field B is scanned from -2 T to +2 T along the out-of-plane direction, while the transverse Nernst voltage is measured simultaneously. The results show that Syx exhibits small relative variation across the entire ±2 T range, with no hysteresis or jumps. This is because MnBi₂Te₄ is a type A antiferromagnet, with a spin-flop critical field of approximately 4 T, much higher than 2 T; below this critical field, the antiferromagnetic configuration remains unchanged, thus the anomalous Nernst response determined by the interlayer Berry curvature is unaffected by the external magnetic field. Furthermore, the switch can be controlled by the out-of-plane electric field. Quantum computing, especially topological quantum computing, requires the application of an additional magnetic field, thus necessitating thermoelectric conversion devices that are immune to magnetic fields. Therefore, the thermoelectric recovery device of this invention is naturally compatible with the operating environment of quantum computing.
[0037] According to one or more embodiments, a method for fabricating a quantum computing heat recovery device based on topological materials, and a method for electrically controlling the performance of the device, are disclosed. The heat recovery device includes:
[0038] Conductive gate layer;
[0039] A topological material thermoelectric conversion layer is located between conductive gate layers;
[0040] The lateral electrode pair, located above and in contact with the thermoelectric conversion layer, is used to read out the lateral Nernst voltage in a direction perpendicular to the temperature gradient.
[0041] Top gate (optional, used in conjunction with bottom gate to form a dual gate for independent control of carrier concentration and displacement field);
[0042] External circuitry (reading out or storing the generated potential energy).
[0043] The external circuit includes: a lead-out module, which connects to a low-temperature lead (such as twisted constantan or NbTi wire) of a transverse electrode pair; the lead-out module is connected to a readout module; the readout module is a high input impedance, low noise voltage readout unit, such as a nanovoltmeter, a low-temperature preamplifier, or a lock-in amplifier; when using AC thermal modulation (heating at frequency f and demodulation at 2f), using a lock-in amplifier can significantly improve the signal-to-noise ratio.
[0044] The fabrication method of quantum computing heat recovery device based on topological materials is as follows:
[0045] Step A: Provide a substrate containing a conductive gate layer, commonly SiO2 / Si (heavily doped Si as the bottom gate).
[0046] Step B, on the substrate obtained in step A, through mechanical dissociation, AlO x Topological antiferromagnetic materials are formed as thermoelectric conversion layers by methods such as assisted dissociation, physical transfer, or molecular beam epitaxy.
[0047] Step C: Fabricate lateral electrode pairs (Hall bar geometry) on the thermoelectric conversion layer obtained in step B to form a heat recovery device;
[0048] Step D: An insulating encapsulation layer is prepared above the thermoelectric conversion layer and the lateral electrode pair. The encapsulation layer can be hBN, Al2O3, SiO2, HfO2, etc., and a top gate and a bottom gate can be prepared on the encapsulation layer to form a dual-gate structure.
[0049] Step E, external circuitry, is used to read out the transverse Nernst voltage signal generated by the device or to store energy in it.
[0050] Here, the overall thickness of the thermoelectric conversion layer (topological material) is less than 100 nm. The electrode material is selected from one or more of the following materials: titanium, palladium, gold, chromium, etc. The selection principle is to reduce the contact resistance between the metal and the material.
[0051] The control methods for heat recovery devices specifically include:
[0052] By applying an out-of-plane displacement field εE to the thermoelectric conversion layer through the gate, the PT symmetry of the system is disrupted, thereby inducing and regulating the magnitude of the interlayer Berry curvature, and thus switching and controlling the magnitude of the anomalous Nernst voltage. Specifically, when the displacement field is zero, the anomalous Nernst voltage is suppressed by symmetry (off state); when the displacement field increases, the anomalous Nernst voltage monotonically increases (on state); and when the direction of the displacement field is changed, the sign of the anomalous Nernst voltage flips accordingly, thereby realizing the all-electric switching, amplitude modulation, and polarity reversal of the heat recovery function. The displacement field can be applied in various ways, including single-gate voltage methods, dual-gate voltage methods, and ferroelectric gate methods. In a dual-gate structure, the carrier concentration and displacement field can be independently controlled.
[0053] Therefore, the core technical means of this disclosure include:
[0054] (1) By utilizing the anomalous Nernst effect of topological (antiferromagnetic) materials, waste heat (temperature gradient) in low-temperature environments (especially quantum computing chips) can be recovered and converted into transverse voltage signals for on-chip heat recovery and thermal management in quantum computing.
[0055] (2) By applying an out-of-plane displacement field to the gate to disrupt the PT symmetry of the system and induce and adjust the interlayer (real space) Berry curvature, an anomalous Nernst response is achieved through all-electric switching, amplitude modulation, and sign flipping, with an on / off ratio exceeding 10. 5 .
[0056] (3) The device operates under zero external magnetic field, relying on an antiferromagnetic topological material with zero net magnetic moment. It neither introduces stray magnetic field nor is it robust to stray magnetic field (about 2T), and is compatible with superconducting quantum bits and magnetic shielding environment.
[0057] (4) Adopting lateral (Nernst) geometry to achieve directional, localized heat extraction and energy recovery, thermal management and energy harvesting are completed simultaneously in the same device, and it can be used as a thermoelectric field-effect transistor (ANFET).
[0058] The technical effects of the embodiments disclosed herein include:
[0059] (a) Achieve zero external magnetic field operation and resist stray magnetic fields.
[0060] The device in this embodiment operates under zero external magnetic field, and because the net magnetic moment of the antiferromagnet is zero, it neither introduces stray magnetic fields nor is it robust to external stray magnetic fields (its response remains essentially unchanged in the range of approximately 2T), and is compatible with superconducting qubits and magnetic shielding environments for quantum computing.
[0061] (b) Achieve electrical adjustability.
[0062] The heat transfer of this device can be achieved through continuous and reversible switching and amplitude modulation of the gate voltage, with an on / off ratio exceeding 10. 5Furthermore, its sign can be flipped, allowing it to be used as an anomalous Nernst field-effect transistor (ANFET), with functionality far exceeding that of traditional ANE devices with fixed output.
[0063] (c) Compared to traditional heat recovery devices, this disclosure is based on the intrinsic quantum geometry effect (Beyley curvature) of topological antiferromagnetic materials, which makes the anomalous Nernst coefficient at low temperature in zero magnetic field the leading one among all materials.
[0064] (d) It possesses lateral (Nernst) geometric advantages. The voltage direction is perpendicular to the temperature gradient direction, which has intrinsic directional control capability, enabling localized and directional heat extraction. It is insensitive to contact resistance and thermal shunting loss, and can simultaneously achieve thermal management and energy recovery in the same device, facilitating micro- and nano-scale on-chip integration.
[0065] (e) Achieve on-chip integration.
[0066] This device can be directly fabricated near or on top of a quantum processor chip, recovering waste heat that is difficult to dissipate in situ into electrical signals, reducing wiring and noise between classical electronics and quantum circuits.
[0067] Figure 1 shows a top view and a front view of the quantum computing heat recovery device based on topological materials according to the present disclosure, illustrating a conductive gate layer (bottom gate, top gate), a topological antiferromagnetic material layer, a lateral metal electrode pair, and a lateral Nernst voltage (Vn).
[0068] Figure 2 is a graph showing the relationship between the transverse Nernst signal (Nernst coefficient Syx) of the heat recovery device according to the present disclosure and the gate voltage, illustrating the on / off ratio achieved by the gate voltage.
[0069] Figure 3 shows the relationship between the transverse Nernst signal (Nernst coefficient Syx) of the heat recovery device according to the present disclosure and the out-of-plane electric field εE, illustrating the on / off state achieved by the out-of-plane electric field.
[0070] Figure 4 is a switching count diagram of the anomalous Nernst signal of the heat recovery device according to the present disclosure, showing the stability after 10,000 switching cycles.
[0071] Figure 5 shows the relationship between the anomalous Nernst signal of the heat recovery device of this disclosure and the applied magnetic field, demonstrating the robustness of the response under stray magnetic fields up to about 2T.
[0072] According to one or more embodiments, a quantum computing heat recovery device based on topological materials, independent of external magnetic fields, and fully electrically tunable is disclosed.
[0073] Quantum computing heat recovery devices based on topological materials include:
[0074] (1) Substrate, usually SiO2 / Si substrate, in which heavily doped conductive Si is used as the bottom gate; it can also be SiN / Si, HfO2 / Si, Al2O3 / Si, etc. The substrate and the top conductive gate layer are used to apply an out-of-plane displacement field to the thermoelectric conversion layer, thereby controlling its PT symmetry breaking and interlayer Bailey curvature, and thus modulating the anomalous Nernst response.
[0075] (2) As shown in Figure 1, a topological material thermoelectric conversion layer is set on the substrate, the thickness of which is usually less than 100 nm (typically four septuple layers of MnBi2Te4, i.e., 4SL MnBi2Te4). The preparation method can be mechanical dissociation, AlO x Methods include assisted dissociation, physical transfer, and molecular beam epitaxy. This topological material should satisfy the following: anomalous Nernst signal is suppressed under zero electric field, while interlayer Bailey curvature can be induced under an out-of-plane electric field.
[0076] (3) Prepare lateral electrode pairs (Hall bar geometry) for the thermoelectric conversion layer to read out the lateral Nernst voltage in a direction perpendicular to the temperature gradient. The electrode thickness is typically between 5 and 200 nm. The electrode material is selected from one or more of titanium, palladium, gold, chromium, etc., with the selection principle being to reduce the contact resistance between the metal and the topological material.
[0077] (4) An insulating encapsulation layer, such as hBN, Al2O3, SiO2, HfO2, etc., is prepared on the thermoelectric conversion layer and the lateral electrode pair, and a top gate is prepared to form a dual-gate structure with the bottom gate to independently control the carrier concentration and displacement field; it can also be used to protect the topological material and isolate the environment. In the dual-gate structure, the device can be independently controlled by applying these two voltages symmetrically or asymmetrically. When Vtg = Vbg (symmetrical application), the carrier concentration (chemical potential) is mainly changed, and the net displacement field changes little; when Vtg ≠ Vbg (asymmetrical application), the magnitude and direction of the out-of-plane displacement field εE can be independently adjusted while keeping the carrier concentration approximately unchanged, thereby precisely controlling the degree of PT symmetry breaking and the anomalous Nernst response. Vtg (top gate conductive electrode (located above the insulating encapsulation layer)) applies an out-of-plane electric field from above the device; Vbg (bottom gate (heavily doped Si substrate)) applies an out-of-plane electric field from below the device.
[0078] (5) Connect an external readout circuit to read out the transverse Nernst voltage signal generated by the device, or to store / drive the recovered potential energy to the load.
[0079] The working principle is as follows: under zero external magnetic field, a gate voltage is applied to the bottom gate (and top gate) of the substrate to generate an out-of-plane electric field εE. When the displacement field is zero, the system is protected by PT symmetry, the anomalous Nernst effect is suppressed, and the device is in the off state. After applying the displacement field, the PT symmetry is broken, inducing a finite interlayer Berry curvature, causing the thermoelectric conversion layer to generate a transverse Nernst voltage under the action of a temperature gradient, and the device is in the on state. The amplitude of this transverse voltage can be continuously controlled by adjusting the gate voltage, and its sign can be flipped by changing the direction of the displacement field, thereby recovering the waste heat of the quantum computing chip into a controllable electrical signal, and realizing local thermal management and energy harvesting.
[0080] According to one or more embodiments, a method for fabricating a quantum computing heat recovery device based on topological materials specifically includes:
[0081] Step 1: Provide a conductive Si substrate with a bottom gate and grow an insulating layer (SiO2, SiN, HfO2 or Al2O3) on it, or directly use a commercial SiO2 / Si substrate.
[0082] Step 2: On the substrate obtained in Step 1, mechanical dissociation / AlO x Even-numbered layers of topological antiferromagnetic materials (such as 4SL MnBi2Te4) are formed using assisted dissociation / physical transfer / molecular beam epitaxy methods as thermoelectric conversion layers.
[0083] Step 3: Prepare a transverse electrode pair on the thermoelectric conversion layer obtained in step 2. The electrode material is selected from one or more of titanium, palladium, gold, and chromium.
[0084] Step 4: An insulating encapsulation layer (hBN, Al2O3, SiO2, HfO2, etc.) is prepared on the thermoelectric conversion layer and the lateral electrode pair, and a top gate can be prepared to form a double gate structure.
[0085] Step 5: Connect the external circuit to the gate voltage source, and read out and store the transverse Nernst voltage signal by adjusting the gate voltage / displacement field switch and controlling the anomalous Nernst response.
[0086] It should be understood that in the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0087] It is worth noting that although the foregoing has described the spirit and principles of this disclosure with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that the features in these aspects cannot be combined; such division is merely for the convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims
1. A quantum computing heat recovery device, characterized in that, The heat recovery unit includes, Bottom grid layer; A first insulating layer is grown on the bottom gate layer; A thermoelectric conversion layer is grown on the first insulating layer; A pair of transverse electrodes is grown on the first insulating layer and electrically connected to the thermoelectric conversion layer; The bottom gate layer applies a first out-of-plane displacement field to the thermoelectric conversion layer through the first insulating layer to switch and regulate the anomalous Nernst effect of the heat recovery unit.
2. The heat recovery unit according to claim 1, characterized in that, The heat recovery unit also includes a grid pressure source for providing a first out-of-plane displacement field.
3. The heat recovery unit according to claim 2, characterized in that, The lateral electrode pair of the heat recovery unit is connected to an external readout circuit, which is used to read out the lateral Nernst voltage signal or recover potential energy to store / drive the load.
4. The heat recovery unit according to claim 2, characterized in that, The heat recovery unit also includes, A second insulating layer is grown on the thermoelectric conversion layer and the lateral electrode pair; Top grid layer; The top gate layer applies a second out-of-plane displacement field to the thermoelectric conversion layer through the second insulating layer. The gate voltage source provides a first out-of-plane displacement field while simultaneously providing a second out-of-plane displacement field.
5. The heat recovery unit according to claim 1, characterized in that, The thermoelectric conversion layer is a lateral thermoelectric conversion layer based on topological materials.
6. The heat recovery unit according to claim 1 or 2, characterized in that, The electrode pair is of Hall bar geometry.
7. The heat recovery unit according to claim 1 or 2, characterized in that, The bottom gate layer is made of heavily doped conductive Si.
8. The heat recovery unit according to claim 3, characterized in that, The thermoelectric conversion layer is a MnBi2Te4 magnetic topological insulator thin film.
9. A method for preparing a quantum computing heat recovery device, characterized in that, This method Includes the following steps, The first insulating layer is grown on the bottom gate layer. A thermoelectric conversion layer of topological antiferromagnetic material and a pair of transverse electrodes connected to the thermoelectric conversion layer are grown on the first insulating layer. A second insulating layer is grown on the lateral electrode pair and the thermoelectric conversion layer; A top gate layer is grown on the second insulating layer; The grid voltage source is connected to an external circuit, which is used to read out the transverse Nernst voltage signal or to store energy. The grid voltage source is used to provide a first out-of-plane displacement field or a second out-of-plane displacement field.